Abstract: In this paper, an expression of the coefficient of reducing cracking resistance in reinforced concrete torsional members under pulling force and a formula for calculating the ctacking resistance are derived, based on the theory of Hsu's inclined bending and concrete characteristics under biaxial strength. According to the theory of space truss with variable angle, the effect of pulling force on torsional ultimate strength of members is analyzed. A formula for calculating ultimate strength of reinforced concrete tortional members is presented. Fourteen reinforced concrete members were tested, and the test results are agreeable with those of the theoretical calculations.