diff --git a/src/hooks/useDataEntities.ts b/src/hooks/useDataEntities.ts
index c618ce7b..3aa1f2c4 100644
--- a/src/hooks/useDataEntities.ts
+++ b/src/hooks/useDataEntities.ts
@@ -27,7 +27,7 @@ export default (treeData: any, fieldNames: FieldNames) =>
           warning(!isNil(val), 'TreeNode `value` is invalidate: undefined');
           warning(!wrapper.valueEntities.has(val), `Same \`value\` exist in the tree: ${val}`);
           warning(
-            !key || String(key) === String(val),
+            isNil(key) || String(key) === String(val),
             `\`key\` or \`value\` with TreeNode must be the same or you can remove one of them. key: ${key}, value: ${val}.`,
           );
         }
diff --git a/src/hooks/useTreeData.ts b/src/hooks/useTreeData.ts
index 58ea4b10..ca54accd 100644
--- a/src/hooks/useTreeData.ts
+++ b/src/hooks/useTreeData.ts
@@ -9,7 +9,7 @@ function buildTreeStructure(nodes: DataNode[], config: SimpleModeConfig): DataNo
 
   nodes.forEach(node => {
     const nodeKey = node[id];
-    const clonedNode = { ...node, key: node.key || nodeKey };
+    const clonedNode = { ...node, key: node.key ?? nodeKey };
     nodeMap.set(nodeKey, clonedNode);
   });
 
diff --git a/tests/Select.spec.tsx b/tests/Select.spec.tsx
index fd22a4e2..0f037514 100644
--- a/tests/Select.spec.tsx
+++ b/tests/Select.spec.tsx
@@ -139,6 +139,21 @@ describe('TreeSelect.basic', () => {
       );
       expect(container.firstChild).toMatchSnapshot();
     });
+
+    it('preserves a numeric zero key in treeDataSimpleMode', () => {
+      const onSelect = jest.fn();
+      const { container } = render(
+        <TreeSelect
+          treeData={[{ id: 'fallback', key: 0, value: 0, title: 'zero' }]}
+          treeDataSimpleMode
+          onSelect={onSelect}
+          open
+        />,
+      );
+
+      fireEvent.click(container.querySelector('.rc-tree-select-tree-node-content-wrapper'));
+      expect(onSelect).toHaveBeenCalledWith(0, expect.objectContaining({ key: 0 }));
+    });
   });
 
   it('sets default value', () => {
diff --git a/tests/Select.tree.spec.js b/tests/Select.tree.spec.js
index 9989bec2..5c0ee88a 100644
--- a/tests/Select.tree.spec.js
+++ b/tests/Select.tree.spec.js
@@ -87,6 +87,16 @@ describe('TreeSelect.tree', () => {
     spy.mockRestore();
   });
 
+  it('warning if numeric zero key is not same as value', () => {
+    resetWarned();
+    const spy = jest.spyOn(console, 'error').mockImplementation(() => {});
+    render(<TreeSelect treeData={[{ title: 'zero', value: 'different', key: 0 }]} />);
+    expect(spy).toHaveBeenCalledWith(
+      'Warning: `key` or `value` with TreeNode must be the same or you can remove one of them. key: 0, value: different.',
+    );
+    spy.mockRestore();
+  });
+
   it('warning if node undefined value', () => {
     resetWarned();
     const spy = jest.spyOn(console, 'error').mockImplementation(() => {});