Abstract: With the development of new energy friendly grid-connected technology and energy storage technology, photovoltaic-battery virtual synchronous generator (PV-battery VSG) will have broad development prospects. However, the dynamic interaction mechanism between multiple PV-battery VSGs and multi-machine power system is not clear, and the possible oscillation problem will bring great risk to the stable operation of grid. Firstly, the state-space models of multiple PV-battery VSGs subsystem and multi-machine power system subsystem are established, and the transfer functions are derived. Then, the dynamic interaction model between two subsystems is established, and the damping torque provided by multiple PV-battery VSGs to multi-machine power system is derived to analyze the path and mechanism of dynamic interaction. Finally, based on the examples of multiple PV-battery VSGs connected to 4-machine 2-area system and 10-machine 39-bus system, the influences of virtual synchronous control and the control parameters on dynamic interaction are analyzed in detail, and the correctness of proposed conclusion is verified by system eigenvalue analysis and time domain simulation.