The design and realization of electro-optical simulation as well as its application in semi-physical emulation test were introduced. In the hardware design, the hardware of electro-optical simulation is based on the industry-control-computer platform. The hardware was designed and realized in order to provide the video simulation image for the tested equipment. In the software design, the electro-optical simulation software was written in Visual C++ programming environment, which supports the functions such as emulated trace creation, video simulation image sending, test data process and evaluation.