3-PRS parallel mechanism is capable of moving along the X and Y axes and rotating around the Z axis,however it also brings parasitic motion in the non-independent DOFs. In order to analyze the parasitic motion of 3-PRS parallel mechanism and obtain changes of motion parameters and structural parameters,the mathematical model of the inverse kinematics is established on the basis of analyzing the structure of 3-PRS parallel mechanism. Parasitic motion in the non-independent is analyzed by simulation software ...