The machinery composition and working principle of 3-TPT parallel machine tool were analyzed. The three dimensional solid models of components of 3-TPT parallel machine tool were designed by using Pro/E. The virtual assembly and connection of the machine tool were accomplished in the assembly environment of Pro/E. Besides, the three-dimensional motion simulation of mechanism about the machine tool was researched in the mechanism module of Pro/E. The three-dimensional animation achieved by the simulation has the strong sense of reality. The working principle of the parallel machine tool was verified by the simulation. The simulation results show that the machine tool has advantages such as good stationarity, no interference and no singularity.