The running characteristics and controller output characteristics of permanent magnet synchronous motor (PMSM) for electric vehicle were introduced. According to the technical conditions and test methods specified in GB/T 18488-2015 “drive motor system for electric vehicle”, the online inspection process for electric vehicle PMSM was designed in combination with the production process planning of PMSM for electric vehicle. On this basis, the online performance inspection system for electric vehicle PMSM was designed, and the advanced frequency conversion measurement technology and computer control measurement technology were applied in the system. Experimental results showed that the system was accurate, stable, easy to operate and highly automatic, and had high design reference value.