To make the rehabilitation training of the elderly more convenient, effective, objective, and diversified, the treadmill is designed into a variety of control modes. Using the existing mechanical structure of the treadmill in the laboratory, an intelligent treadmill control system with a man-machine interaction function is designed. The control system mainly includes STM32F105 microprocessor, permanent magnet synchronous AC motor, stepper motor, electric push rod, tension sensor. The STM32F105 microprocessor is used as the master control unit of the control system. The QT upper computer controls the lower computer through the UART2 serial communication protocol and carries out data transmission through Ethernet. The running machine has speed regulation mode, front and back pitching mode, left and right turnover mode, and weight loss mode. The data of the whole control system is fed back to the upper computer in real-time, which realizes the function of man-machine interaction very well. The real-time performance and stability of the whole control system are good through system tests.