Abstract: This article introduced the application of fault detection robot technology in the EMU fault detection, researched on the robot technology to replace manual work on EMU chassis fault detection, solved the problem of excessive maintenance pressure and insufficient maintenance capacity. Through the use of the fault detection robot system of EMU, it was reduced the effects on inaccuracy and low work efficiency caused by manual fault detection, decreased the dependence on manual detection, improved the efficiency, work quality and fault detection accuracy of EMU maintenance, and provided the data basis for the big data analysis of CRH. The article studied and described the composition, function, the specific design and the implementation of the flexible structure of the system in detail.