Abstract: An improved frequency converter test system of mine-used hydraulic pump was proposed in order to meet demands of performance testing and debugging of spare parts and repaired hydraulic pump after hydraulic pump was fault, and solve the problems that common hydraulic pump test system has low automation level, large workload on recorded data processing. Hydraulic system, frequency-conversion control system, information collection system and software system of the system were introduced in details. The system can quickly collect signals of hydraulic pump pressure, flow, rotational speed and torque, and can automatically complete efficiency test, impact test, load test, overload test and speed test of the hydraulic pump. The system has obvious saving effect with power recovery rate of 60% in full load and overload test.