Along with the industry and the motor control system performance and the intelligent request's unceasing enhancement, the PID control technology application is getting more and more widespread. This article use TMS320F2812 DSP of TI is a core, outside expands SRAM. This system control actuation closed loop direct current machine by the F2812, DSP controls electrical machinery's rotational speed and the direction through CPLD. It control electrical machinery's rotational speed by PID algorithm reaction. This system realized TMS320F2812 not to brush electrical machinery's control regarding the cocurrent, the main characteristic uses the digital PID controller, the original simulation PID controller hardware will realize the function realized with the software, it with simulated the PID controller to compare the merit is: Has the very strong flexibility, may test and experience the online adjustment parameter according to the experiment, may obtain the better control performance.