Abstract: Taking the 3-TPT parallel machine tool developed by this university as example, the two different methods resolving the workspace problem of parallel machine tool are discussed. One is to solve the kinematical inverse equation of parallel machine tool, then the available workspace is found out by analytical method. The other one is using the virtual prototype technique instead of the analytical method as above to resolve the workspace problem. It is such a method that is simple and clear in thought process as a shortcut and available to use in wide range, i.e. only a model of virtual prototype of parallel machine tool is needed to develop with some constraint conditions given, the workspace can be found out directly without complex derivation process. The two methods mentioned above are compared with each other, and the results indicate that the method by virtual prototype technique is more visual and practical and simpler.