In the traditional motor test system, it is impossible to directly test the transient parameters of the motor and the requirements of dynamic arbitrary load loading when the motor is loaded or the problem of high implementation cost. This research uses STM32+FPGA as the core to form the main control of the motor test system Unit, combines with the superior control performance of the ARM processor and the high-speed data processing advantages of FPGA. The FPGA and STM32 are controlled by the FSMC bus communication and data ping-pong algorithm. Through above method, there is a small-size control core board manufactured in the motor test system. It can be embedded in the existing traditional dynamometer system to improve the dynamometer transient parameter test and dynamic motor loading performance. Experimental results show that the system can basically meet the requirements of motor transient test and dynamic loading, and can achieve the fastest data refresh rate of 1 ms for measuring the measured motor’ s speed and torque, and arbitrary waveform loading within 100 M sampling frequency, with a loading error of 0. 8%. It satisfies the motor transient test and dynamic loading requirements.