In view of the fact that train maintenance requires a lot of manpower and material resources，the hardware platform and software design of the Locomotive EMC testing platform based on NI data acquisition system are proposed, and the detailed structure is introduced. And through the detection of the actual surge pulse, the platform detection data is compared with the data recorded by the oscilloscope, and the error is 0.6%. The detection platform can monitor the surge pulse current of the cable inside the locomotive, which helps to diagnose and troubleshoot the EMC of the locomotive. The system can also be extended to monitor EMC problems such as transformer operating conditions and vehicle operating conditions.