diff --git a/paimon-core/src/main/java/org/apache/paimon/mergetree/compact/aggregate/FieldCountAgg.java b/paimon-core/src/main/java/org/apache/paimon/mergetree/compact/aggregate/FieldCountAgg.java
index f03290cb81a9..5fb7b2bb9e75 100644
--- a/paimon-core/src/main/java/org/apache/paimon/mergetree/compact/aggregate/FieldCountAgg.java
+++ b/paimon-core/src/main/java/org/apache/paimon/mergetree/compact/aggregate/FieldCountAgg.java
@@ -38,7 +38,7 @@ String name() {
     public Object agg(Object accumulator, Object inputField) {
         Object count;
         if (accumulator == null || inputField == null) {
-            count = (accumulator == null ? 1 : accumulator);
+            count = (accumulator == null ? (inputField == null ? 0 : 1) : accumulator);
         } else {
             // ordered by type root definition
             switch (fieldType.getTypeRoot()) {
@@ -59,7 +59,7 @@ public Object agg(Object accumulator, Object inputField) {
     public Object retract(Object accumulator, Object inputField) {
         Object count;
         if (accumulator == null || inputField == null) {
-            count = (accumulator == null ? 1 : accumulator);
+            count = (accumulator == null ? (inputField == null ? 0 : -1) : accumulator);
         } else {
             // ordered by type root definition
             switch (fieldType.getTypeRoot()) {
diff --git a/paimon-core/src/test/java/org/apache/paimon/mergetree/compact/aggregate/FieldAggregatorTest.java b/paimon-core/src/test/java/org/apache/paimon/mergetree/compact/aggregate/FieldAggregatorTest.java
index e164bda31f21..5bca65ed74a4 100644
--- a/paimon-core/src/test/java/org/apache/paimon/mergetree/compact/aggregate/FieldAggregatorTest.java
+++ b/paimon-core/src/test/java/org/apache/paimon/mergetree/compact/aggregate/FieldAggregatorTest.java
@@ -155,10 +155,11 @@ public void testFieldSumIntAgg() {
     @Test
     public void testFieldCountIntAgg() {
         FieldCountAgg fieldCountAgg = new FieldCountAgg(new IntType());
-        assertThat(fieldCountAgg.agg(null, 10)).isEqualTo(1);
-        assertThat(fieldCountAgg.agg(1, 5)).isEqualTo(2);
-        assertThat(fieldCountAgg.agg(2, 15)).isEqualTo(3);
-        assertThat(fieldCountAgg.agg(3, 25)).isEqualTo(4);
+        assertThat(fieldCountAgg.agg(null, null)).isEqualTo(0);
+        assertThat(fieldCountAgg.agg(1, null)).isEqualTo(1);
+        assertThat(fieldCountAgg.agg(null, 15)).isEqualTo(1);
+        assertThat(fieldCountAgg.agg(1, 0)).isEqualTo(2);
+        assertThat(fieldCountAgg.agg(3, 6)).isEqualTo(4);
     }
 
     @Test