With the rapid development of intelligence and networking， the number and complexity of electronic and electrical control units（ECUs）in new energy vehicles have multiplied. It is particularly important that ECU can quickly find the cause in case of failure. Diagnosis technology is a specific method to confirm the cause of vehicle ECU fault. This paper takes diagnosis technology as the research object. Firstly， the development of UDS protocol for automotive diagnosis is introduced， and the content of UDS protocol is clarified. Secondly， it explains how to use the diagnostic UDS protocol for the development and design of Automotive ECU， and further explains how to meet the requirements of vehicle factory off-line electrical inspection，after-sales service，software upgrade and other application scenarios. Finally，the new development of diagnosis technology in automotive remote service is prospected. Through this design， we can fully grasp the apply of diagnosis technology in the automotive design and development， and play a positive role in improving ECU fault diagnosis and safety performance.