In this paper, a mechanical model for a half-tracked vehicle with eight degrees of freedom is established. A scheme of active disturbance rejection control (ADRC) is first presented to control the vertical motion and pitching angle of the tracked vehicle. The inner parameters uncertainty and the external disturbances are estimated as the total disturbances by using extended state observer (ESO) and are then real-time compensated by the control law. Tracked vehicle suspension system under random road excitation is simulated by MATLAB. The results show that ADRC has better control effect towards the acceleration and pitching angle of the suspension system comparing with the fuzzy controller.