In order to solve the problem of low complexity, low running energy consumption and so on, the design method of complex complex path tracking control system of multi degree of freedom robot based on ultrasonic is proposed. Through the interface circuit design of the control system of MAX232 chip, the construction of monitoring circuit with low power consumption CMOS monitoring circuit chip MAX706, ultrasonic wave can provide accurate robot with obstacle distance information, such as a barrier will receive the information converted to form electrical signals back to the main control board. The software uses the program of the main board controller and the design of ultrasonic ranging program. The experimental results show that the designed control system can improve the recognition rate of the obstacle and reduce the energy consumption of the system.