In order to study the influence of Elastohydrodynamic Lubrication (EHL) on the dynamics characteristics of cylindrical meshing gears, this paper established a dynamic model of cylindrical meshing gears coupled with EHL based on the dynamic theory. An improved dynamic transmission error model considering EHL is proposed, which is brought into the coupled cylindrical meshing gear dynamic model. The dynamics and EHL characteristics of the coupled improved model, the general model in the existing literature and the gear pair in dry contact are compared. The effects of input speed, output load, presence or absence of lubrication and the viscosity of lubricating oil on the dynamic characteristics of the gear are analyzed and verified by experiments. The results show that the root mean square value of longitudinal acceleration of driving wheel increases gradually with the increase of input speed; With the increase of output load, the root mean square value of longitudinal acceleration of driving wheel increases gradually; Gear lubrication greatly weakens the vibration; The improved model is more in line with the working conditions of gear system, and has some reference significance for the future research of gear dynamics.