Abstract: In order to study the load bearing and deformation capacity of a large-span half steel-plate-reinforced concrete (HSC) beam, a static test of a scaled down (1∶3) simply supported specimen is conducted. The mechanical characteristics and damage process of the HSC specimen are investigated by analyzing the development of the deflection, strain and fracture during loading process. Good combination action is observed during the test in steel plates, reinforcing bars and concrete in HSC beam;and the specimen has good mechanical properties of high bearing capacity, large stiffness and high ductility. At last, the calculation formulae for the bending capacity and short-term stiffness of the composite beam in existing codes are examined via the experimental results and theoretical analysis, which provides a reference for engineering design.