Abstract: In order to study the flexural performance of a novel prestressed steel-encased concrete composite beam with corrugated steel webs, four bending tests were carried out taking prestressed tendons, the number of shear connectors and the width of concrete slab as parameters. Results show that corrugated steel can work well with concrete, effectively strengthen the steel-concrete interface to avoid the occurrence of longitudinal slip failure. However, its axial stiffness is small and contributes little to bending capacity. Prestress and the concrete flange plate have a greater contribution to the bending capacity of the composite beam, and the longitudinal horizontal shear failure occurs when the number of shear connectors is insufficient. On the basis of experimental study, the finite element model is established. Results show that the new composite beam can take full advantage of the combined functions of each component and improve the flexural capacity and ductility of the specimen. Compared with the straight steel composite beam, the corrugated steel composite beam has better rigidity and higher bearing capacity. With the increase of concrete strength, the bearing capacity increases slightly. With the increase of the thickness of the lower flange plate, the bearing capacity of the steel plate is significantly increased, which has little influence on the stiffness. Stiffness and bearing capacity increase with the increase of prestressing degree, but ductility decreases. Finally, a calculation formula of flexural capacity is derived.