<p>The angular misalignment between the contacting teeth is common failure in gear transmission, which directly affect the contact characteristics and transmission accuracy of gear system. In this paper, a time-varying mesh stiffness (TVMS) model of spur gear in elastohydrodynamic lubrication (EHL) condition, considering the influence of angular misalignment, is established based on the slice coupling principle. The proposed model considers the coupled effect of misalignment error and EHL state on the contact characteristics of the meshing interface to obtain a revised contact stiffness, which is further combined with the torsional stiffness resulting from angular misalignment to determine the comprehensive TVMS. The oil film properties at the meshing interface are solved using the Reynolds equation. The total contact stiffness of sliced meshing tooth in EHL contact is obtained from parallel action of solid nonlinear Hertz stiffness and oil film stiffness. The coupling stiffness between the adjacent sliced tooth arisen by the un-uniform load distribution due to angular misalignment is also considered to determine the deformation of sliced tooth, and to update the mesh stiffness of the single tooth pair. The modified TVMS with angular misalignment in EHL condition are further substituted into the 6 degrees-of-freedom dynamic model to investigate the dynamic responses. Effects of misalignment error on dynamic responses of the gear system are analyzed. Experiments under different gear angular misalignments are performed to verify the proposed model. The developed model provides a promising basis for the accurate dynamic performance prediction of the gear transmission system.</p>