Abstract: The plastic and heat treatment processes of integrated molding of TC4 titanium alloy torque tube would change the mechanical properties relative to the base metal. To obtain accurate material constitutivity, a method of determining the real stress and strain relationship based on tube torsion test is derived. Then, the shear stress-strain relationship of the cross section of TC4 titanium alloy tube are obtained by analyzing the experimental data based on this method, and the finite element model of the pipe tube is established for simulation analysis. Comparing the simulation results with the experimental data, the results of the simulation and the experimental data are highly consistent, which proves the feasibility and engineering practicability of this method.