Digital signal processor (DSY) is a necessary component in power electronic digital control.Since the traditional DSY application system design cycle is too long,a virtual DSY module is built using MAST language of Saber simulation software.The work process of DSY can be simulated by the module,which can be controlled by C program in CCS development environment.Taking the event manager of DSY for example,the design method and work principle of the virtual module are described.The program is designed in Visual C++.Finally,the Buck circuit and the control system based on the virtual DSY are built.Based on the method,the design and debugging cycle would be greatly shorted.The simulation and experimental results verify the effectiveness of the proposed method.