This paper proposes a discrete particle swarm optimization (DPSO) to solve the multiple destination routing (MDR) problems. The problem has been proven to be NP-complete and the traditional heuristics (e.g., the SPH, DNH and ADH) are inefficient in solving it. The particle swarm optimization (PSO) is an efficient global search algorithm and is promising in dealing with complex problems. This paper extends the PSO to a discrete PSO and uses the DPSO to solve the MDR problem. The global search ability and fast convergence ability of the DPSO make it efficient to the problem. Experiments based on the benchmarks from the OR-library show that the DPSO obtains better results when compared with traditional heuristic algorithms, and also outperforms the GA-based algorithm with faster convergence speed.