In structural design of high-rise buildings, due to large upper loads or span, the beam section height is large, which usually affects the effective story height and the total height of building. To reduce the height of beam-slab structure and increase the clearance height of each floor effectively, a new connection method of composite beam-slab structure with steel-box beam embedded was proposed. As for the new connection method, monotonic loading tests were carried out on composite connection area of six steel-concrete slabs with steel-box beam embedded, to study the negative moment resistant. The difference in negative moment resistant capacity between the concrete composite floor with steel-box beam embedded and the concrete composite floor with traditional stud connection was analyzed. The finite element analysis was carried out by using ABAQUS. Experimental results and finite element analysis show that, as for the connection method of composite beam-slab with steel-box beam embedded, the negative moment resistant capacity of concrete slab has no significantly difference with the concrete slab with traditional stud connection.