The workspace of the parallel robot is an important index to evaluate the working ability of the parallel mechanism, and the structural parameters are the basic factors that affect the workspace. The workspace of the attitude was determined by the arc intersection method, and the cross-sectional shape was obtained. The volume of the workspace was calculated by the trapezoidal integral method. Taking the workspace volume as the objective function, the structural parameters of the mechanism were optimized by genetic algorithm, and the structural parameters with excellent performance were obtained. The workspace diagram of the parallel mechanism was obtained by MATLAB software, and the change of the workspace could be observed more intuitively. It lays foundation for further research and popularization of the parallel mechanism.