We consider an optimization method that updates multi searching points based on piecewise rotational chaos system. In previous, some optimization methods utilizing chaos dynamics have been proposed. The considered method is simpler than these methods because it has two system parameters and the searching points are governed by single dynamics. We compared the performance of the considered method for 27 benchmark functions with particle swarm optimization and a previous proposed chaos-based method. The considered method obtains the best performance for 16 functions and tie for 2 functions. The Friedman test shows that the considered method obtains significancy better than both methods.