Dithering particle swarm optimization (DPSO) algorithm is introduced into adaptive polarization stabilization in a 40 Gb/s optical communication system. The DPSO algorithm has the merits of rapid convergence to the global optimum, without being trapped in local sub-optima, and good robustness to noise. How to implement DPSO as a component of a control algorithm in adaptive polarization stabilization is described. Performance comparisons between PSO and DPSO were carried out theoretically and experimentally. It is demonstrated that fast changes of SOP can be successfully tracked using the DPSO algorithm.