A method for dynamic performance optimization of continuously variable transmission speed ratio control valve based on improved particle swarm optimization algorithm is presented. First at all, a dynamic model was set up by means of mechanism analysis to predict the valve dynamic performance. Then, an objective function for optimization was established considering dynamic performance indices of speed ratio control valve such as response time, overshoot and saving energy based on its operating requirements. Finally, the optimization problem was solved by using an improved particle swarm optimization algorithm with necessary constraints. The properties of the optimized valve were compared with the prototype workpiece, and the results indicated that the dynamic performance indices of the optimized valve were much better than those of the prototype workpiece.