Abstract: The formula solutions of elastic stresses and the limit torque of reducing elbows subject to twisting moments were validated according limit element analysis (LMA) and testing. The results of LMA shows that the effect of twisting moment on the end of reducing elbows is just similar to that of reducing elbows subject to in-plane close-bending moments. The effect of a twisting moment turns to be a bending moment during transferring along a bend pipe was validated gradually. The results of LMA with a smaller end subject to a twisting moment are show that the most stresses lie on outside the arch of the smaller end of reducing elbows, and the error is not overrun with 5 percent. It is mean that the testing result is consistent with formula solutions but it is a little dangerous. The testing results of a larger end subject to a twisting moment show that the stress level of a smaller end is higher than that of the larger end of reducing elbows. The formula solutions of limit torques are safety than that of most testing results clearly.