Based on the similarity principle, a reduced scale test model of steel-concrete joint section of The Xiamen Maxin Bridge is designed to investigate the mechanical behavior of steel-concrete joint section of hybrid beam cable-sayed bridges. The test model is loaded with design load and 1.7 times design load, and the variations of stress and deformation of control sections and main members with loading history are obtained. Combining test results with numerical simulation results, the load transfer mechanism of steel-concrete composite joint section is researched. As shown in the results, the stress of steel, concrete and PBL connector of the joint section is small, and there is enough safety capacity in the joint section. The relative slip between steel box and concrete is small, the steel box and concrete work together well, and the load from steel is smoothly delivered to concrete. The load distribution of load-transmission members is proper. It is proved by the test that the lattice with post-bearing plate and PBL shear connectors is reasonable for steel-concrete composite joint section.