In view of the converter control system, puts forward the direct torque control method based on ARM. The hardware and software of the converter for milling machine are designed; ARM control system is mainly composed of acquisition module, power module and memory unit, etc., and ARM processor detects the temperature and pressure signals of the locomotive and communicates with the DSP to control the milling machine converter. Experiments show that the control system is capable of real-time monitoring the locomotive operation and recording the temperature and pressure value of each device.