The invention relates to a self-propelled aerial working platform vehicle chassis, which belongs to the field of engineering machinery. The chassis is provided with a frame, the frame is respectively articulated with a front axle and a rear axle through main chassis shafts, the body of a four-sided slide valve is fixed on one side of the frame, a four-sided slide valve core pull rod is articulated with the rear axle, the body of a left servo hydraulic cylinder is articulated with the frame, the piston rod of the left servo hydraulic cylinder is articulated with the front axle, the body of a right servo hydraulic cylinder is articulated with the frame, the piston rod of the right servo hydraulic cylinder is articulated with the front axle, a hydraulic power source supplies oil to the four-sided slide valve under constant pressure, one oil outlet of the four-sided slide valve is connected with the piston cavity of the right servo hydraulic cylinder and the rod cavity of the left servo hydraulic cylinder via a balance valve, and the other oil outlet of the four-sided slide valve is connected with the rod cavity of the right servo hydraulic cylinder and the piston cavity of the left servo hydraulic cylinder. The invention adopts the mechano-hydraulic servo control mechanism to ensure that tyres can follow the ground to ensure driving force, and the tread can be automatically increased and decreased in the process of running.