To improve the solving efficiency and performance,a new Discrete Particle Swarm Optimization(DPSO) algorithm for the problem of weapon-target assignment(WTA) was presented,in which the velocity and position in the original PSO formulas were redefined to solve a discrete combination optimization such as WTA.The greedy heuristic policies were exploited to adjust the solutions generated during the execution of the algorithm to find optimal or suboptimal solution rapidly.The experiments show that the new algorithm can get the optimal or suboptimal solution quickly,and the result is satisfying.