Abstract: The virtual simulation injection molding machine is an effective tool for carrying out equipment operation training and the virtual experimental injection molding. However, there are many types of injection molding machines, and the control panels, molding parameters and injection molding machine movements of each type of injection molding machine are different. The use of a single model of virtual injection molding machine does not meet the needs of use. By extracting the common features of injection molding machine, designing a common base class, And then deriving a unique sub-class according to the characteristics of different types of injection molding machines, it is convenient to expand and design a multi-model virtual injection molding machine system. The example shows that the method is effective and can meet the needs of use.