Abstract: Nowadays, the speed of engineering construction is getting faster and faster, the mechanical and electrical system is very important in some engineering projects, so people also put forward higher requirements for the mechanical and electrical system. However, in the actual work process, because the mechanical and electrical system often appears in the operation of a variety of faults, so the scientific maintenance and management of the mechanical and electrical system is of great significance, it can effectively improve the operating efficiency of mechanical and electrical system. Therefore, in this paper, the composition of the mechanical electrical system is briefly introduced at first, then the main points of the design of the mechanical electrical system are analyzed, and finally, some effective treatment measures are discussed for the common mechanical electrical system faults, hope to further improve the level of mechanical and electrical system operation.