This paper mainly deals with the kinematic analysis and performance comparisons of three redundant parallel mechanisms for fracture reduction surgery. First, two novel kinematically redundant parallel mechanisms for surgical robots are proposed based on the Gough-Stewart parallel platform. The kinematics of the three mechanisms are established, and their workspaces are analyzed. The analysis result shows that the workspace volume of the redundant mechanism can be improved by 71.6%. Second, considering the stroke of redundant actuators, the effects of the slider strokes on the position and orientation workspaces are obtained. The multi-objective optimization method is used to optimize the geometric parameters of the three mechanisms. Third, the singularities of the three redundant parallel mechanisms are compared based on the dimensionally homogeneous Jacobian matrix. Finally, experiments are conducted to verify the effectiveness of the performance comparison methods in this paper.