To solve the problems of transient overvoltage and poor voltage stability in new energy generation systems, this paper proposes a transient voltage suppression method based on particle swarm optimization algorithm. By determining the voltage optimization objective of the sending end AC system, the method needs to select the control parameters of high voltage crossing reactive current and low voltage crossing active current, and at the same time consider the safe operation of the power grid and the actual adjustable range of parameters, set optimization constraints to ensure the transient stability of the system, and then use particle swarm optimization algorithm to optimize parameters, Specifically, it includes parameter initialization, particle swarm initialization, execution of optimization algorithms, and updating the position and speed of particles through multiple iterations, so as to finally obtain the approximate optimal parameter settings. In the design of transient control strategy, two control strategies are adopted for photovoltaic inverter converter during fault: 1. Traditional PI control strategy; 2. Photovoltaic SDRE control strategy to suppress high voltage at the sending end. The transient overvoltage suppression method based on particle swarm optimization algorithm in this paper not only significantly improves the voltage stability of new energy generation system, but also enhances the adaptive ability and overall performance of the power grid.