The utility model discloses an automatic balancing system for a chassis of a self-propelled harvesting machine. The automatic balancing system comprises an upper-layer mounting main frame, a lower-layer chassis frame, a sensor mounting platform, an inclination angle sensor, an automatic control system and a balancing hydraulic system, the sensor mounting platform serves as a reference plane for the tilt angle sensor to monitor the tilt angle; the tilt angle sensor is used for acquiring tilt information of the upper-layer mounting main frame relative to the ground; the automatic control systemis used for acquiring a control signal and a level signal of the tilt angle sensor; the balance hydraulic system comprises a hydraulic base station and a single-rod double-acting piston hydraulic cylinder and is used for adjusting the relative position relation between the upper-layer installation main frame and the lower-layer chassis frame and executing a lifting instruction sent by the automatic control system to conduct profiling. According to the utility model, the adaptability and the stability of the self-propelled working machine under complex environmental conditions are improved, theworking efficiency and the working accuracy are improved, and the working labor intensity of workers is reduced.