As a new design pattern, virtual optimization design is a multiple subjects crossed synthetical technique and will become the trend of modern mechanical products design. It can avoid the repeated processes from design to trial-manufacture and test. The designers can analyze and optimize the product structures in virtual visualization environment. The design cycle is shortened and the cost is reduced. The paper analyzes the peculiarity of virtual optimization design, and puts forward the thought and procedure to implement virtual optimization design. Finally, the example to optimize the NC lathe headstock is studied.