Abstract: To study the bending performance and failure modes of embedded steel-concrete composite beams with built-up doubleT-shaped webs(DTWCB), four composite beams were designed and fabricated for symmetric third-point loading tests. During the fabrication of the specimens, the steel webs of the T-beams were cut into a dovetail configuration, and two T-beam are welded together through a transverse diaphragm to form a double-T-beam. The dovetailed steel webs were then embedded into the concrete flange plate to form a shear connector. The effects of the width of the concrete flange plate, the thickness of the steel beam web and flange plate, and the spacing between shear connectors on the bending capacity of composite beams were evaluated. The results show that DTWCB exhibit good bending performance, characterized by typical flexural failure. The specimens demonstrated significant mid-span vertical deflection prior to failure. Varying the width of the concrete flange plate has a minimal impact on the bending capacity of the composite beam. When the thickness of the steel plate is increased from 4 mm to 6 mm, the ultimate bearing capacity of the composite beam increases by 18.6%. Increasing the spacing between shear connectors reduces the bending capacity. Based on the test results and relevant specifications, formulas for calculating the bending capacity and stiffness of the composite structure were established, providing a reference for the design of such composite structures.