Abstract: The main parameters affecting the shear strength of the reinforced concrete (RC), partial prestressed concrete (PPC) and prestressed concrete (PC) simply supported beams are analyzed and optimized; and the expression formula for the shear strengths of the concrete and the hooped reinforcement are putforward respectively. Based on the experimental results obtained bythe projectresearchteamand the regression analysis of the data tested in 871 beams from home and abroad, the united formulas for calculating the shear strengths of the RC, PPC and PC simply supported beams are presented, which have been adopted as the shear provision of“China Railway Bridge Code”.