Abstract: A new particle swarm optimizer, called stochastic PSO, that is guaranteed to converge to the global optimization solution with probability one, is presented based on the analysis of the standard PSO. And the global convergence analysis is made using the Solis and Wets’ research results, and two methods of stopping evolution particle to be regenerated are given. Finally, several examples are simulated to show that SPSO is more efficient than the standard PSO.