In order to help patients with wrist injuries to carry out recovery training, a simple and portable parallel 3-RSR wrist rehabilitation mechanism was introduced in order to achieve the expected therapeutic effect. Firstly, the parallel 3-RSR wrist rehabilitation mechanism is described. Taking the parallel mechanism as the research object, the degree of freedom is calculated and the pose is solved by analytical method, which verifies the rationality of the mechanism motion. Then, based on the boundary search method, the reachable workspace of the parallel wrist rehabilitation mechanism is analyzed, and the relevant workspace map is drawn. Finally, considering the reasonable optimization of the structural size of the workspace, the results show that the optimized reachable attitude workspace is significantly larger than the initial workspace. This study provides a theoretical reference for the ontology design of rehabilitation institutions.