Abstract: Adopting the Timoshenko's beam theory of considering transvers shear deformation, the material nonlinear analysis of RC beams have been done by using layered finite element method.In the analysis,a method with which neutral axis is approximated by using itera tion technology.In respect of the material,the cracking of concrete in tension,the aggregate interlock,the tension stiffening and dowel action after cracking of concrete are considered.In addition,the ductile behavior of concrete in compresion is represented with nonaniform hardening plasticity theory.Compared with others,the method in this paper has the advantages of the simplicity of data preparation and effectiveness of computation.