diff --git a/packages/core/src/main.ts b/packages/core/src/main.ts
index 76d6de7..d3ae188 100644
--- a/packages/core/src/main.ts
+++ b/packages/core/src/main.ts
@@ -24,14 +24,12 @@ if(process.env.NODE_ENV === 'development') {
   console.info(`%cquarkc@${version}`, 'color: white;background:#9f57f8;font-weight:bold;font-size:10px;padding:2px 6px;border-radius: 5px','Running in dev mode.')
 }
 
-type Falsy = false | 0 | '' | null | undefined
-
 /** 
- * Check if val is empty. Falsy values except than 'false' and '0' are considered empty.
+ * Check if val is null or undefined.
  * 
- * 判断是否为空值，falsy值中'false'和'0'不算
+ * 判断是否为空值，
  */
-const isEmpty = (val: unknown): val is Exclude<Falsy, false | 0> => !(val || val === false || val === 0);
+const isEmpty = (val: unknown): val is (null | undefined) => val == null;
 
 const defaultPropertyDeclaration: PropertyDeclaration = {
   observed: true,
@@ -231,6 +229,7 @@ function getWrapperClass(target: typeof QuarkElement, style: string) {
           }
 
           const isBoolProp = type === Boolean;
+          const hasConverter = isFunction(converter);
           /** convert attribute's value to its decorated counterpart, that is, property's value */
           const convertAttrValue = (value: string | null) => {
             // * For boolean properties, ignore the defaultValue specified.
@@ -238,16 +237,15 @@ function getWrapperClass(target: typeof QuarkElement, style: string) {
             if (
               !isBoolProp
               && isEmpty(value)
-              && !isEmpty(defaultValue)
             ) {
               return defaultValue;
             }
 
-            if (isFunction(converter)) {
-              return converter(value, type);
+            if (!hasConverter) {
+              return value;
             }
 
-            return value;
+            return converter(value, type);
           };
           const dep = new Dep();
           Props.set(this, attrName, {
@@ -261,7 +259,7 @@ function getWrapperClass(target: typeof QuarkElement, style: string) {
             propName,
             {
               get(this: QuarkElement) {
-                dep.depend()
+                dep.depend();
                 return convertAttrValue(this.getAttribute(attrName));
               },
               set(this: QuarkElement, val: string | boolean | null) {
@@ -491,23 +489,13 @@ export class QuarkElement extends HTMLElement implements ReactiveControllerHost
     this.rootPatch(newRootVNode);
   }
 
-  /** update properties by DOM attributes' changes */
+  /** sync property with its attribute counterpart */
   private _updateObservedProps() {
     (this.constructor as QuarkElementWrapper)._observedAttrs.forEach(
-      ([attrName, {
+      ([_, {
         propName,
-        options: {
-          type,
-          converter,
-        },
       }]) => {
-        let val = this.getAttribute(attrName);
-
-        if (isFunction(converter)) {
-          val = converter(val, type);
-        }
-        
-        this[propName] = val;
+        this[propName] = this[propName];
       }
     );
   }
diff --git a/packages/core/test/comp.test.ts b/packages/core/test/comp.test.ts
index 8b4975b..f445a9a 100644
--- a/packages/core/test/comp.test.ts
+++ b/packages/core/test/comp.test.ts
@@ -82,8 +82,8 @@ describe('@property', () => {
     const camelCaseNode = comp.shadowRoot?.querySelector('.test1-camelcase');
     expect(node).to.exist;
     expect(camelCaseNode).to.exist;
-    expect(node!.textContent).to.equal('0');
-    expect(camelCaseNode!.textContent).to.equal('camelcased');
+    expect(node!.textContent).to.equal('lowercased');
+    expect(camelCaseNode!.textContent, 'camelcased name share the same value with lowercased name').to.equal('lowercased');
     comp!.setAttribute('testattr', '1');
     await nextTick();
     expect(node!.textContent).to.equal('1');
@@ -176,6 +176,16 @@ describe('@property', () => {
     await nextTick();
     expect(node!.textContent).to.equal('welcome to japari park!');
   });
+
+  it('not set, use default value', async () => {
+    const comp = await render();
+    const node = comp.shadowRoot?.querySelector('.test8');
+    expect(node).to.exist;
+    expect(node!.textContent).to.equal('18');
+    comp!.setAttribute('testattr8', '1');
+    await nextTick();
+    expect(node!.textContent).to.equal('1');
+  });
 });
 
 describe('Fragment', () => {
diff --git a/packages/core/test/components/test-property.tsx b/packages/core/test/components/test-property.tsx
index 66f3d07..dc46184 100644
--- a/packages/core/test/components/test-property.tsx
+++ b/packages/core/test/components/test-property.tsx
@@ -15,7 +15,7 @@ declare global {
 @customElement({ tag })
 class TestProperty extends QuarkElement {
   @property()
-  testattr = '0';
+  testattr = 'lowercased';
 
   /** except for initial value, will work the same as testattr */
   @property()
@@ -44,6 +44,9 @@ class TestProperty extends QuarkElement {
   @property({ type: Boolean })
   testattr7 = true;
 
+  @property({ type: Number })
+  testattr8 = 18;
+
   /** boolean property with its value default to true should be ignored */
   @property({ type: Boolean, attribute: 'aria-hidden' })
   testAriaHidden = false;
@@ -60,6 +63,7 @@ class TestProperty extends QuarkElement {
         <div className="test6">{this.testattr6.join(' ')}</div>
         <div className="test7">{this.testattr7.toString()}</div>
         <div className="test7-aria">{this.testAriaHidden.toString()}</div>
+        <div className="test8">{this.testattr8.toString()}</div>
       </div>
     );
   }