For studying the dynamic characteristics and lubrication performance of high speed involute spur gear, a tribo-dynamic model considering the temperature rise of tooth surface contact is proposed to analyze the coupling relation between lubrication characteristics and dynamic behavior, for revealing the lubrication mechanism. Firstly, a multiple degrees of freedom (DOFs) bending-torsional coupling dynamic model for spur gear is established, which consists of time-varying meshing stiffness, backlash and transmission error. Then, a one-dimensional line contact transient thermalelastohydrodynamic lubrication (TEHL) model is built up. A tribo-dynamic model of spur gear with thermal effect is proposed by means of integration, and an iterative calculation integrated the Runge-Kutta method and the multigrid method is utilized to solve the governing equations of coupled system. Finally, the necessity of establishing tribo-dynamic coupling model is proved by comparing the numerical results of static and dynamic conditions.The analysis of tribo-dynamic characteristics and the comparison of temperature rise, provesthe improvement of dynamic characteristics and lubrication performance of high speed gears.