Abstract Lubrication and vibration are crucial to the reliability and efficiency of gear device, especially in high-speed, heavy-load condition. In this study, a novel model based on tribo-dynamic theory is introduced to investigate the lubricating and dynamic performances of high-speed spur gear. In conjunction with a finite element model, the time-varying meshing stiffness and static transmission error are derived precisely in the form of Fourier series. An efficient iterative algorithm, integrated Newmark method with multigrid method, is developed for solving the governing equations. The simulation results indicate that it is necessary to utilize tribo-dynamic model to assist lubrication design and vibration control of spur gear in high-speed condition.