Because of the special forms of the suspensions of the mining dump truck (MDT), common methods can not be used to solve the problem of “braking nod”. In view of those, based on the neutral plane and the moment center, suspension parallel bench test simulation and vehicle braking simulations were conducted to get the wheels' contact point trajectory and the suspension longitudinal angle stiffness and so on. And then, the value of suspension longitudinal stability coefficient was obtained. It was identified as the target function, and the optimal variables were the suspension parameters, the pitching performance of MDT was optimized. The simulation result has shown that the suspension longitudinal stability coefficient is increased by 19.04%, the nodded size of the front suspension and the pitch angle decreased by 18.23% and 15.25%, respectively. The “braking nod” phenomenon of the mining dump truck was improved noticeably.