Abstract: To solve the problem of a lack of theoretical guidance in the simplification process of space pipe truss structure, the equivalent bending moment of inertia of space pipe truss structure was deduced by using the knowledge of material mechanics, and the corresponding calculation formula was put forward. Based on the principle of equal torsional strain energy, the formulas for calculating the equivalent thin plate thickness of the web members and the top and bottom lateral bracing of the pipe truss were derived, and the continuous equivalent section was constructed. The formula for calculating the equivalent torsional moment of inertia of the space pipe truss structure was proposed by using the thin-walled bar theory. The cantilever method was used to verify the accuracy of the calculation formula of equivalent moment of inertia. The equivalent analysis of the tennis court of Lanzhou Olympic Sports Center was carried out. The results show that the formula for calculating the equivalent moment of inertia is reasonable, and its error is within 4% compared with that of the cantilever method. Under the action of deadweight, the errors of the maximum displacement value and the maximum stress value between the original structure and the simplified structure of the tennis court are less than 9%. The vibration modes of the first five steps of the original structure are similar to those of the simplified structure, and their errors of the natural frequency are less than 4%, so the simplified structure has high accuracy.