Abstract: In view of problems of large amount of maintenance and high failure rate existed in actual running process of mine-used electric locomotive used traditional DC speed regulation system, a speed regulation system of mine-used electric locomotive based on permanent magnet synchronous motor was designed. The system uses TMS320F28335 as control core and realizes high-precision control of the electric locomotive combining with strategy of direct torque control as well as peripheral circuits of current sampling, speed measurement. The experimental result shows that the system has good speed regulation performance, fast dynamic response and less maintenance.