With the research and development of a university in hydraulic dynamometer test, we designed a lower machine based on PLC, and giving the power distribution cabinet, electrical and mechanical control system combined with King View software, SIEMENS WINCC software. This study has hand and automatic operation, sensor measuring tank pressure, the measured current measurement power motor, the measurement results sent to our remote devices by Profibus-dp, such as the design of computer use (PC) and remote operation apparatus (Chu Moping). Due to frequency converter is circular soft starting control structure, the motor has no impact at the time of the launch, and stable performance is good, this can improve the service life of the motor and pump greatly.