Abstract: A new type of connection between hollow floor slab and steel beam for assembled staggered truss structure was proposed, and a finite element model based on ABAQUS was established to study its mechanical properties. Based on the finite element model of 17 beam and slab connections, the influence of the parameters such as the height, strength and embedding depth of the T-type connecting steel plate, bolt strength, the diameter of penetrating steel bar, whether there is penetrating steel bar or not, and the strength of post-cast concrete on the bearing capacity of the beam and slab joints was studied. The results showed that: setting T-type connecting steel plate would affect the failure position of post-cast concrete, which would cause the phenomenon of stress concentration; with the increase of the height of T-type connecting steel plate, the stiffness of beam slab joint was also increasing, but it had little effect on the ultimate bearing capacity; the embedding depth of T-type connecting steel plate was the key factor that affected the bearing capacity of beam slab joints, the greater the embedment depth, the greater the bearing capacity; the strength of T-type connecting steel plate, bolt strength and diameter of through reinforcement had little influence on the bearing capacity, while the strength of post cast concrete had a certain influence on the bearing capacity of beam slab joints, the greater the strength, the greater the bearing capacity; the shear capacity of the beam slab joint increased with the increase of the diameter of the shear reinforcement, when the diameter of the reinforcement was larger than 20 mm, the increase of the bearing capacity was limited, and the maximum shear stress could meet the needs of the actual project.