Abstract: In order to enhance the convergence and distribution of multi-objective particle swarm optimization, an improved particle swarm optimization algorithm is proposed. This algorithm adds two operations based on PSO algorithm, one is to update phase normal cast points to improve the algorithm's search capabilities in the population mutation operation optimization. The other one is using the updated way that is in a first in and last out manner in the external repository updates phase.and it is to use an external repository update after update phase advanced way out,and all non-dominated solutions obtained are allowed into the external repository, and then remove the particle of the short distance. Test results by ZDT1-ZDT4 function calculation shows that the algorithm can effectively improve the convergence and distribution.