diff --git a/.github/workflows/platform-ci.yml b/.github/workflows/platform-ci.yml
index f8be8e9912..ea65785c64 100644
--- a/.github/workflows/platform-ci.yml
+++ b/.github/workflows/platform-ci.yml
@@ -179,6 +179,8 @@ jobs:
             mv .coverage build/.coverage.test_ray_dag.file
             pytest $PYTEST_CONFIG --durations=0 --timeout=200 -v -s mars/deploy/oscar/tests/test_ray_dag_failover.py
             mv .coverage build/.coverage.test_ray_dag_failover.file
+            pytest $PYTEST_CONFIG --durations=0 --timeout=200 -v -s mars/deploy/oscar/tests/test_ray_dag_oscar.py -m ray
+            mv .coverage build/.coverage.test_ray_dag_oscar.file
             
             coverage combine build/ && coverage report
           fi
diff --git a/mars/deploy/oscar/ray.py b/mars/deploy/oscar/ray.py
index e17ac0ffdc..1e3edb28c7 100644
--- a/mars/deploy/oscar/ray.py
+++ b/mars/deploy/oscar/ray.py
@@ -37,6 +37,7 @@
     AbstractClusterBackend,
 )
 from ...services import NodeRole
+from ...services.task.execution.api import ExecutionConfig
 from ...utils import lazy_import, retry_callable
 from ..utils import (
     load_config,
@@ -310,6 +311,7 @@ async def new_cluster(
     worker_num: int = 1,
     worker_cpu: int = 2,
     worker_mem: int = 2 * 1024**3,
+    backend: str = None,
     config: Union[str, Dict] = None,
     **kwargs,
 ):
@@ -330,6 +332,7 @@ async def new_cluster(
         worker_num,
         worker_cpu,
         worker_mem,
+        backend,
         config,
         n_supervisor_process=n_supervisor_process,
     )
@@ -402,6 +405,7 @@ def __init__(
         worker_num: int = 1,
         worker_cpu: int = 2,
         worker_mem: int = 4 * 1024**3,
+        backend: str = None,
         config: Union[str, Dict] = None,
         n_supervisor_process: int = DEFAULT_SUPERVISOR_SUB_POOL_NUM,
     ):
@@ -413,6 +417,7 @@ def __init__(
         self._worker_num = worker_num
         self._worker_cpu = worker_cpu
         self._worker_mem = worker_mem
+        self.backend = backend
         # load config file to dict.
         self._config = load_config(config, default_config_file=DEFAULT_CONFIG_FILE)
         self.supervisor_address = None
@@ -434,6 +439,37 @@ async def start(self):
             logging.basicConfig(
                 format=ray.ray_constants.LOGGER_FORMAT, level=logging.INFO
             )
+        execution_config = ExecutionConfig.from_config(
+            self._config, backend=self.backend
+        )
+        self.backend = execution_config.backend
+        if self.backend == "mars":
+            await self.start_oscar(
+                self._n_supervisor_process,
+                self._supervisor_mem,
+                self._worker_num,
+                self._worker_cpu,
+                self._worker_mem,
+            )
+        elif self.backend == "ray":
+            execution_config.merge_from(
+                ExecutionConfig.from_params(
+                    backend=self.backend,
+                    n_worker=self._worker_num,
+                    n_cpu=self._worker_num * self._worker_cpu,
+                    mem_bytes=self._worker_mem,
+                )
+            )
+            assert self._n_supervisor_process == 0, self._n_supervisor_process
+            await self.start_oscar(
+                self._n_supervisor_process, self._supervisor_mem, 0, 0, 0
+            )
+        else:
+            raise ValueError(f"Unsupported backend type: {self.backend}.")
+
+    async def start_oscar(
+        self, n_supervisor_process, supervisor_mem, worker_num, worker_cpu, worker_mem
+    ):
         logger.info("Start cluster with config %s", self._config)
         # init metrics to guarantee metrics use in driver
         metric_configs = self._config.get("metrics", {})
@@ -450,7 +486,7 @@ async def start(self):
             self._config.get("cluster", {})
             .get("ray", {})
             .get("supervisor", {})
-            .get("sub_pool_num", self._n_supervisor_process)
+            .get("sub_pool_num", n_supervisor_process)
         )
         from ...storage.ray import support_specify_owner
 
@@ -466,11 +502,11 @@ async def start(self):
         self._config["cluster"]["lookup_address"] = self.supervisor_address
         address_to_resources[node_placement_to_address(self._cluster_name, 0)] = {
             "CPU": 1,
-            # "memory": self._supervisor_mem,
+            # "memory": supervisor_mem,
         }
         worker_addresses = []
         if supervisor_standalone:
-            for worker_index in range(1, self._worker_num + 1):
+            for worker_index in range(1, worker_num + 1):
                 worker_address = process_placement_to_address(
                     self._cluster_name, worker_index, 0
                 )
@@ -479,11 +515,11 @@ async def start(self):
                     self._cluster_name, worker_index
                 )
                 address_to_resources[worker_node_address] = {
-                    "CPU": self._worker_cpu,
+                    "CPU": worker_cpu,
                     # "memory": self._worker_mem,
                 }
         else:
-            for worker_index in range(self._worker_num):
+            for worker_index in range(worker_num):
                 worker_process_index = (
                     supervisor_sub_pool_num + 1 if worker_index == 0 else 0
                 )
@@ -495,7 +531,7 @@ async def start(self):
                     self._cluster_name, worker_index
                 )
                 address_to_resources[worker_node_address] = {
-                    "CPU": self._worker_cpu,
+                    "CPU": worker_cpu,
                     # "memory": self._worker_mem,
                 }
         mo.setup_cluster(address_to_resources)
@@ -525,7 +561,7 @@ async def start(self):
                     addr,
                     {
                         "numa-0": Resource(
-                            num_cpus=self._worker_cpu, mem_bytes=self._worker_mem
+                            num_cpus=worker_cpu, mem_bytes=self._worker_mem
                         )
                     },
                     modules=get_third_party_modules_from_config(
@@ -543,7 +579,7 @@ async def start(self):
         )
         cluster_state_ref = self._cluster_backend.get_cluster_state_ref()
         await self._cluster_backend.get_cluster_state_ref().set_config(
-            self._worker_cpu, self._worker_mem, self._config
+            worker_cpu, self._worker_mem, self._config
         )
         # start service
         await start_supervisor(self.supervisor_address, config=self._config)
@@ -596,7 +632,9 @@ def __init__(self, cluster: RayCluster, session: AbstractSession):
 
     @classmethod
     async def create(cls, cluster: RayCluster) -> "RayClient":
-        session = await _new_session(cluster.supervisor_address, default=True)
+        session = await _new_session(
+            cluster.supervisor_address, default=True, backend=cluster.backend
+        )
         client = RayClient(cluster, session)
         AbstractSession.default._ray_client = client
         return client
diff --git a/mars/deploy/oscar/tests/test_ray_dag_oscar.py b/mars/deploy/oscar/tests/test_ray_dag_oscar.py
new file mode 100644
index 0000000000..41d28c8c6c
--- /dev/null
+++ b/mars/deploy/oscar/tests/test_ray_dag_oscar.py
@@ -0,0 +1,54 @@
+# Copyright 1999-2021 Alibaba Group Holding Ltd.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import os
+
+import pytest
+
+from ....tests.core import require_ray
+from ....utils import lazy_import
+from ..ray import new_cluster, _load_config
+from ..tests import test_local
+
+ray = lazy_import("ray")
+CONFIG_FILE = os.path.join(os.path.dirname(__file__), "local_test_with_ray_config.yml")
+
+
+@pytest.fixture
+async def create_cluster(request):
+    param = getattr(request, "param", {})
+    ray_config = _load_config(CONFIG_FILE)
+    ray_config.update(param.get("config", {}))
+    client = await new_cluster(
+        supervisor_mem=1 * 1024**3,
+        worker_num=2,
+        worker_cpu=2,
+        worker_mem=1 * 1024**3,
+        backend="ray",
+        config=ray_config,
+    )
+    async with client:
+        yield client, param
+
+
+@require_ray
+@pytest.mark.asyncio
+async def test_iterative_tiling(ray_start_regular_shared2, create_cluster):
+    await test_local.test_iterative_tiling(create_cluster)
+
+
+@pytest.mark.asyncio
+@require_ray
+async def test_execute_describe(ray_start_regular_shared2, create_cluster):
+    await test_local.test_execute_describe(create_cluster)
diff --git a/mars/deploy/oscar/tests/test_ray_scheduling.py b/mars/deploy/oscar/tests/test_ray_scheduling.py
index 47f42b3454..141ff99964 100644
--- a/mars/deploy/oscar/tests/test_ray_scheduling.py
+++ b/mars/deploy/oscar/tests/test_ray_scheduling.py
@@ -235,7 +235,7 @@ async def test_auto_scale_in(ray_large_cluster):
         assert await autoscaler_ref.get_dynamic_worker_nums() == 2
 
 
-@pytest.mark.timeout(timeout=150)
+@pytest.mark.timeout(timeout=500)
 @pytest.mark.parametrize("ray_large_cluster", [{"num_nodes": 4}], indirect=True)
 @require_ray
 @pytest.mark.asyncio
diff --git a/mars/services/task/execution/ray/executor.py b/mars/services/task/execution/ray/executor.py
index f49371575e..fb651ca0f6 100644
--- a/mars/services/task/execution/ray/executor.py
+++ b/mars/services/task/execution/ray/executor.py
@@ -356,7 +356,6 @@ def get_execution_config(self):
 
     # noinspection DuplicatedCode
     def destroy(self):
-        self._config = None
         self._task = None
         self._tile_context = None
         self._task_context = {}
@@ -377,6 +376,7 @@ def destroy(self):
         self._cur_stage_first_output_object_ref_to_subtask = dict()
         self._execute_subtask_graph_aiotask = None
         self._cancelled = None
+        self._config = None
 
     @classmethod
     @alru_cache(cache_exceptions=False)
@@ -518,7 +518,7 @@ def _on_execute_aiotask_done(_):
                 max_retries=subtask_max_retries,
             ).remote(
                 subtask.subtask_id,
-                serialize(subtask_chunk_graph),
+                serialize(subtask_chunk_graph, context={"serializer": "ray"}),
                 subtask_output_meta_keys,
                 is_mapper,
                 *input_object_refs,
diff --git a/mars/services/task/execution/ray/tests/test_ray_execution_backend.py b/mars/services/task/execution/ray/tests/test_ray_execution_backend.py
index a723da00c0..a4a39c9268 100644
--- a/mars/services/task/execution/ray/tests/test_ray_execution_backend.py
+++ b/mars/services/task/execution/ray/tests/test_ray_execution_backend.py
@@ -124,6 +124,7 @@ async def test_ray_executor_create(
     assert mock_task_state_actor_create.call_count == 1
 
 
+@require_ray
 @pytest.mark.asyncio
 async def test_ray_executor_destroy():
     task = Task("mock_task", "mock_session")
@@ -150,6 +151,7 @@ async def test_ray_executor_destroy():
     assert await executor.get_progress() == 1.0
 
 
+@require_ray
 def test_ray_execute_subtask_basic():
     raw = np.ones((10, 10))
     raw_expect = raw + 1
diff --git a/mars/services/task/execution/utils.py b/mars/services/task/execution/utils.py
index ade928df81..648c0953ae 100644
--- a/mars/services/task/execution/utils.py
+++ b/mars/services/task/execution/utils.py
@@ -24,7 +24,7 @@ def get_band_resources_from_config(
     n_worker: int = config["n_worker"]
     n_cpu: int = config["n_cpu"]
     mem_bytes: int = config["mem_bytes"]
-    cuda_devices: List[List[int]] = config["cuda_devices"]
+    cuda_devices: List[List[int]] = config.get("cuda_devices")
 
     bands_to_resource = []
     worker_cpus = n_cpu // n_worker