In order to study the influence of tire, suspension and cargo box on the roll stability of dump truck under different working conditions, an analysis method based on the rollover contribution degree was proposed. A four-degree-of-freedom nonlinear mathematical model for vehicle lifting operation was established. And MATLAB/Simulink was used to simulate the model under different input conditions of lateral slope angle and cargo eccentric load. Then the variation law of tire, suspension and cargo box rollover contribution degree under the critical lift state of the vehicle was obtained. The results show that the rollover contribution degree can effectively reflect the main influencing factors of vehicle roll stability under different working conditions.