Abstract: Six parameters are used to build up the inverse kinematics model for the 6 PSS parallel mechanism, that is, to compute the displacement of each dieblock according to the given position and orientation of the cutter. The unique value of each dieblock is determined based on moving continuity. During the trajectory planning, positions and orientations of the cutting tool at any moment can be obtained, and the corresponding displacements of the dieblocks can be calculated. In order to display the machining process visually, the simulation software has been developed using the three dimensional graphics development software package OpenGL. The analysis given proves that both the method of modeling and the interpolation algorithm are valid, thus providing a basis for practical system development.