The study aims at the internal ballistics optimization problem of the multi-gas generators pulse launching power system. On the premise of satisfying the ballistic index and focusing on the coordination and matching of missile load and ejection power efficiency, a modular gas generator internal trajectory model was established. PSO was used to optimize the internal ballistics design of the multi-gas generators pulse launching power system. The global optimal solution was obtained. The results indicate that the particle swarm optimization algorithm proposed with the objective function of the efficiency of the ejection power done in the launcher is an efficacious approach for solving the optimization problem of the eject power system. The optimized ignition timing strategy can achieve an efficiency rate of 85.27% for the ejection power system. The simulation results have certain theoretical guidance significance for the design of the multi-gas generators pulse launching power system.