A two rotational degree of freedom (2DOF) of spatial parallel mechanism was proposed. They were rotated around two different directions, one direction perpendicular to the fixed platform, rotating about the Z axis, and the other one parallel to the moving platform which changed with the movement of the parallel mechanism continuously. The kinematic screw and constraint screw of the limbs of mechanism were analyzed according to the constraint screw theory, and the DOF was also calculated. The rationality of the original input selection was judged. In the last, position equation of the parallel mechanism is established by using DH method to build the coordinate system of every connecting rod.