Abstract: With pipe racking device of offshore drilling platform as object of the research, this study builds its kinematic model on the basis of its actual motion in the pipe racking process and solves this model by the method of homogeneous coordinate transformation, then the position and posture of the PRS end effector (clamp) during the racking procedure can be achieved which is relative to the inertial reference system. The motion track and the displacement, velocity and acceleration curves of clamp are acquired by MATLAB software. The kinematic parameters of this mechanism are analyzed comparatively when the joints are in the three different motion modes: Uniform velocity, uniform acceleration-uniform deceleration and uniform acceleration-uniform velocity-uniform deceleration.