<p>The purpose of this paper was to analyze the influence of cumulative wear on the coexistence response and meshing state transition of gear system under mixed elastohydrodynamic lubrication. Firstly, the time-varying geometric parameters and motion parameters of gears under positive meshing and reverse impact were analyzed and then the non-uniform wear model and equivalent mixed elastohydrodynamic lubrication model of gears were established, the coupling of lubrication model and gear meshing model were considered. On this basis, the dynamic model of gear system was improved, and the nonlinear dynamic model of gear considering meshing state transition, time-varying meshing characteristics, time-varying backlash and lubrication coupling characteristics was established. The cell mapping method was used to transfer the general nonlinear local analysis to the global analysis depending on the initial state of the system. The influence of non-uniform cumulative wear on the parameter bifurcation characteristics of the coexistence response, the evolution characteristics of the attraction domain and the transition process of the meshing state was discussed. The results show that the degree of wear affected the type and amplitude of the coexistence response of the gear, and damaged the transition of the gear meshing state and the load-bearing condition of the gear teeth.</p>