Aiming at the problem of automatic control of walking speed of wheeled selfpropelled square baler, an automatic control system of walking speed of wheeled selfpropelled square baler based on workload feedback was designed. The working principle and control characteristics of the belt transmission CVT were analyzed. The overall design of the control system and design of hydraulic circuit were completed. The mathematical model of the transmission ratio and cylinder elongation of CVT was established. In order to balance the speed and stability of the vehicle speed adjustment, the control system program was divided into vehicle speed adjustment control and vehicle speed stability control, which ensured that the vehicle speed adjustment control program can achieve the target vehicle speed in a short time; the stability control program was designed to stabilize the speed of the vehicle under subsequent working conditions. For road loadincreasing and loadreducing test, the threshold value was 0.2km/h and the allowable deviation was 0.1km/h. The maximum dynamic deviation was less than 5%, and the maximum residual deviation was less than 1%. It took less than 5s for the speed to reach stability. The control system can automatically control the speed according to the simulated load of the machine, and can realize the switching between the automatic walking control and the manual walking control, which provided a certain reference value for the intelligent adjustment of walking speed of general chassis of wheeled selfwalking combine harvester.