To simplify weapon equipment safeguard resource project optimization, particle swarm optimization (PSO) algorithm was chosen to solve the resource-constrained project scheduling problem (RCPSP). The determinations of activities sequence with relation constraint, the solution space of RCPSP and the repair strategy and the calculation of particle fitness were introduced in detail. Application to a certain type of weapon equipment safeguard resource project optimization example using the PSO program given shows us the validity of using PSO to solve RCPSP and can bring us great military benefit to improve the fighting ability of weapon equipment.