Concerning the problem of low convergence accuracy and being easily to fall into local optimum of the Particle Swarm Optimization (PSO), an improved PSO algorithm combined Centroid and Cauchy Mutation, namely CCMPSO, was proposed. Firstly, at the initialization stage, chaos initialization was adopted to improve the ability of initial particle uniform distribution.Secondly, the concept of centroid was introduced to improve the convergence rate and optimization capability. By calculating the global centroid of all the particles in the population and the individaual centroid formed by all of the individuals' extreme values, sufficient information sharing could be realized in the interior of the particle swarm. To avoid falling into local optimal solution, Cauchy mutation operation was used to perturb the current optimal particle, in addition, the step length of disturbance was adaptively adjusted according to the operation rule of Cauchy mutation; the inertia weights were also dynamically adjusted according to population diversity. Finally, seven classical test functions were used to verify the algorithm. Experimental results indicate that the new algorithm has good performance in convergence precision of the function execution results, including the mean, the variance and the minimum value.