Spatial parallel mechanism of a novel 4—SPS/CU that can perform three-dimensional rotations and translation about Z axis was presented. The parallel mechanism of 4—SPS/CU, with SPS-limp regarded as the driver and CU-limp regarded as the driven, was synthesized. The principles that the mechanism could perform the above motions were analyzed based on the screw theory, and the degree of freedom of the mechanism was calculated. The forward and reverse solutions of position analysis were presented, then the Jacobian matrix of the mechanism was derived and its velocity, acceleration performance, singular configuration and workspace were analyzed.