In this paper, the current numerical simulation method for RC shallow beams is summarized. Using different FE model and constitutive model, two RC beams from experiment conducted and documented by Bresler et. are analyzed. By comparing analysis and experiment results, the best combination of FE model and constitutive model used for numerical simulation is pointed out; explanation for differences between analysis and experiment results has been given out. Furthermore, the study shows that ultimate bearing capacity of beams should not be simply determined as the imposed load when the solution is not converged but be related to strain of concrete in compression region and stress of reinforcement in thensile region. At last, the sensitivity of some parameters is studied by single factor method. All the conclusions from this paper will promote the standardization of numerical simulation of RC beams.