A waterwave method based on chaotic mapping algorithm for the fast search algorithm of planar parallel mechanism workspace is put forward in the study. Taking the 3-RRR parallel mechanism as a example,the reachable workspace,certain posture workspace and dexterous workspace are analyzed. A rotation ability evaluation index is defined to analyze the mechanism rotation capacity inside workspace and visualization drawing by MATLAB,the distribution of rotational capacity in the working space is intuitively reflected. Finally,the mechanism is optimized by genetic algorithm to improve the mechanism rotational ability.