According to the characteristics and situation of the principle of engineering structure design, experimental teaching demonstration system was designed independently based on the virtual instrument, which combined computer technology with testing technology closely. The data processing and interface display program for the experimental teaching demonstration had functions of experiment types selection, parameter setting, graphics real-time display, and data storage and reproduction. Practice result shows that the demo system provides a friendly and open platform for students to carry out the engineering structure experiments, which has a broad application prospect.