Aiming at the misalignment problem of the support bearing in the planetary gear transmission system of a tracked vehicle， the equation of motion of the planetary gear-rotor system with bearing tilt misalignment was established. A bearing force model was proposed based on the nonlinear Hertz contact theory， which could be considered when the ball bearing was respectively in the condition of inner/outer ring tilt misalignment. The proposed model was coupled with the lumped mass model of planetary gear and the finite element model of rotor， and the dynamic model of planetary gear transmission system was obtained. The influence of bearing misalignment on the system dynamic characteristics was analysed， and the evolution law of the parameters such as raceway curvature radius and initial bearing radial clearance on the system dynamic characteristics was further discussed. The results show that the bearing tilt misalignment lead to the sharp increase of bearing contact force， the periodic fluctuation of contact angle， contact stiffness and bearing clearance， the increase of varying compliance （VC） vibration frequency amplitude and the decrease of system amplitude. Enhancing the raceway curvature radius and bearing initial clearance can increase the VC vibration. However， the appropriate selection of large bearing clearance can offset the adverse effects caused by tilt misalignment of bearing installation.