According to the actual requirement of the numercial control (NC) rotational table for manufacturing, the three degree of freedom (3-DOF) parallel configuration 3-PUS-RU is treated as the research object. The position inverse kinematic equation with the closed vector method and the Jacoiban matrix of the parallel manipulator were established. The workspace and stiffness performance index of the parallel manipulator were introduced, and the distribution map of the workspace and the conservative congruence transformation (CCT) stiffness of the coordinates of the mechanism were drawn. The results show that the workspace and stiffness performance are still symmetrical distributed due to the symmetry of the parallel manipulator, so the work area should select the location with stiffness as large as possible. The research result done on the workspace and the CCT stiffness performance of the 3-PUS-RU parallel configuration has some guidance function for the design of the parallel manipulator.