Abstract: The design of structural parameters and the simulation of motor-driven 6-DOF parallel manipulators were researched to solve the problems such as more restriction conditions, complicated interference and longer design periods during parallel manipulator design. Taking the Stewart parallel manipulator as an example, two methods of solving the workspace of parallel manipulators were discussed. Firstly, the workspace was solved by the geometric method, and then a method to solve the workspace and the load-bearing capacity by the virtual prototype technique was proposed. It is such a method that the three-dimensional design is developed through Pro/E software and the three-dimensional model is diverted to Adams software for dynamic simulation. Simulation results show that this method avoids tedious calculations and reduces the design period on condition that the simulation results are reliable.