An experimental study on bonded prestressed steel-reinforced concrete frames at an early stage was conducted to investigate the constraint imposed by steel in the prestressed steel-reinforced concrete beam to concrete and its impact on the carrying capacity of the frame beam. Test results show that steel can effectively restrain concrete deformation in the core area, improve the brittleness of concrete under pressure when it is destroyed, and enhance the flexural bearing capacity of the beam. With regard to prestressed steel-reinforced concrete frame beams in bending, and with reference to the theory of confined concrete as described in the literature, a bearing capacity calculation method for prestressed steel-reinforced concrete frame beams considering regional constraints is proposed based on the superposition principle. The calculated results of the flexural bearing capacity of prestressed steel-reinforced concrete beams are compared with the test results in the limit state. The average ratio of the calculated results to the test results is 0. 98, demonstrating agreement between them.