Abstract: To investigate the flexural performance of a steel-reinforced concrete composite beam with light-weight concrete, the nonlinear finite element program named SRCBNP was developed and combined with the program developed in the relevant references. A serial of specimens in the experimental investigation are selected as the subjects to be simulated respectively, the load-deflection behaviors and failure modes were derived, and forming and development of crack and crushing of concrete in SRCB-1 were obtained, and the analytical results agree well with the test conclusions. Moreover a series of design parameters such as RC strength and section composition were further analyzed, the influence behavior of them were summarized to provide the theoretical basis for relative specifications and code amendments.