By introducing the span-to-height ratio,this paper deduces wo evaluating equations of shear strength of simple reinforced concrete beamwith stirrups and under uniform loads.This makes the shear stressing concept consistent with the evaluating equations,thus improves the evaluating equationsof shear strength of the New Code.Two equations are provided with auto-regulating function on shear strength for a cross section of beam.They aresimple and convenient in evaluation.The working time used for design is not increased and 10% of stirrups is economized in frequent conditions of span-to-height ratio.