Abstract: In the development process of key parts of temporary support device in rectangular tunnel, in order to study the adaptability of the top beam with different types of load as well as stress of the guide rail in the support of the column movement, structural mechanics analysis with ANSYS was done, and the stability of the device was tested on the spot. The research results showed that the largest displacement of the top beam was at the center position. Under high stress load, the top beam was in elastic state when length was 4 m, and plastic damage was done when length was 5 m, indicating that the temporary support device could adapt to the support of 4 m to 5 m width. The guide rail at the 5^# column force was the most unfavorable, the stress concentration degree was the highest, and the bending moment was the biggest. Therefore, in the strength design of the guide, the stress of the 5^# column of the largest bending moment should be emphasized. After experiment, the pressure was stable, the action was flexible and reliable, and the phenomenon of leakage was not appeared. The scheduled goal and requirements was basically achieved.