In order to test the communication function of the ECU before the ECU is mounted on the Bus, it is based on the OSI network layered architecture. This testing process developed a series of CAN bus test countermeasures and procedures in detail. In the past, network testing was mainly done through manual measurement and analysis. The steps of these tests can be planned and designed in advance. Execute the entire testing process in an automated manner, and the reproducibility part is the feature of automated testing. For a complete and detailed test, the environmental parameters and exact test steps should be repeatable to ensure the consistency of test results.