Planetary gear transmission system is widely used in tracked vehicle equipment because of its high load, stable operation and efficient transmission characteristics. The lubrication and dynamic characteristics of planetary gear transmission as well as the interaction between them have an important impact on the whole planetary transmission system, but most scholars often ignore the interaction between tooth lubrication and system dynamic behavior. In this paper, the elastohydrodynamic lubrication model is firstly derived and constructed, then the planetary gear dynamic equation is derived and the planetary gear dynamic model is established, and then dynamic model of the planetary gear transmission system considering gear lubrication is established. Finally, the dynamic response of the planetary gear transmission under different torques and different speeds is obtained based on the coupling model. It is found that the lubrication characteristics of planetary gears have a significant influence on the dynamic behavior of the transmission system under the high speed and light load condition. In this paper, the interaction law between the lubrication of the tooth surface and dynamic behavior of the gear is studied, and it can provide theoretical basis for further study of gear dynamics system.