diff --git a/test/unittest/mock/dm_comm_tool_mock.cpp b/test/unittest/mock/dm_comm_tool_mock.cpp
index adc96723072ed9651807d3471367deba6a254a62..115575ae4c87936a38341d5a8c89ba74edccbd72 100644
--- a/test/unittest/mock/dm_comm_tool_mock.cpp
+++ b/test/unittest/mock/dm_comm_tool_mock.cpp
@@ -22,21 +22,33 @@ namespace DistributedHardware {
 int32_t DMCommTool::SendUserIds(const std::string rmtNetworkId,
     const std::vector<uint32_t> &foregroundUserIds, const std::vector<uint32_t> &backgroundUserIds)
 {
+    if (DMCommToolMock::dmDMCommTool == nullptr) {
+        return 0;
+    }
     return DmDMCommTool::dmDMCommTool->SendUserIds(rmtNetworkId, foregroundUserIds, backgroundUserIds);
 }
 
 int32_t DMCommTool::SendUserStop(const std::string rmtNetworkId, int32_t stopUserId)
 {
+    if (DMCommToolMock::dmDMCommTool == nullptr) {
+        return 0;
+    }
     return DmDMCommTool::dmDMCommTool->SendUserStop(rmtNetworkId, stopUserId);
 }
 
 int32_t DMCommTool::CreateUserStopMessage(int32_t stopUserId, std::string &msgStr)
 {
+    if (DMCommToolMock::dmDMCommTool == nullptr) {
+        return 0;
+    }
     return DmDMCommTool::dmDMCommTool->CreateUserStopMessage(stopUserId, msgStr);
 }
 
 int32_t DMCommTool::SendUninstAppObj(int32_t userId, int32_t tokenId, const std::string &networkId)
 {
+    if (DMCommToolMock::dmDMCommTool == nullptr) {
+        return 0;
+    }
     return DmDMCommTool::dmDMCommTool->SendUninstAppObj(userId, tokenId, networkId);
 }
 } // namespace DistributedHardware