Abstract: The particle's trajectory of PSO was fully analyzed in this paper, the influence of random parameters on par- tide's trajectory was discussed,the concept of cluster-degree was put forward and distribute status of particle with dif- ferent cluster-degree was studied. The reasonable parameters setting range based on cluster-degree was proposed,at the same time,reinforce strategy of particle's velocity was proposed in order to improve performance of PSO under some condition. So this paper is helpful for the choosing and a山ustment of PSO parameters in practical application.

Key words: Particle swarm optirniGation, Cluster-degree, Velocity reinforce strategy