With the continuously increasing ERP implementation, how to define master data, especially manufacturing leadtime is a difficult problem faced by all the manufacturers. Based on VMT (Virtual Manufacturing Technology), the article discusses how to integrate ERP and VMT to help solve it. By running simulation modeling, we can calculate manufacturing leadtime for each operation on the workcell, and thus get the whole routing manufacturing leadtime. This method not only calculates manufacturing leadtime, but also solves the capability planning problem. With the help of VMT, R&D engineers can then supply the exact solutions to prepare master data for ERP system.