This paper evaluate on torsion strength of reinforced concrete beam by using thin-walled tube theory, skew-bending theory, GBJ 10-89 in China, and soften truss model. And, that solution will reveals to experimental data. Above-mentioned, the different evaluations have the different assumption effect in result. The result of predictions shows that the soften truss model proposed by Hsu (1988) reveals close correlation to experimental data.