With the deepening of the concept of environmental protection, the traditional power system dominated by thermal generators has gradually transformed into new-type power system dominated by renewable energy. The influence of large-scale renewable energy plants on the dynamic characteristics of the power system cannot be ignored. Based on the actual operating data, the simulation shows that the start-up capacity of renewable energy has a significant impact on the dynamic stability of new energy grid-connected system after large disturbance. In view of the situation, this article focuses on the dynamic stability problem after large disturbance and analyzes the influence of power flow transfer, equivalent inertia and control parameters of new energy on the dynamic stability, which will be verified by simulation.