Abstract: In order to solve the problems of reduced bearing capacity and large deformation of concrete composite slabs without protruding rebars， reinforcement methods such as setting grooves at the edges of the prefabricated bottom slabs and pasting fiber-reinforced composites at the cross-seam positions of the slab bottom are proposed. Through the static load tests of one monolithic cast slab and eight concrete composite floor slabs without protruding rebars， a comparative analysis was carried out on the flexural characteristics， failure modes， bearing characteristics， and deformation capacities of the specimens.The results showed that the bearing capacity， stiffness， and ductility of the closely spliced composite slab specimens were significantly smaller than those of the monolithic cast slab. Through the strengthening measures such as grooving at the edge of the slab and pasting fiber composites across the cracks at the bottom of the slab， the stress transfer and integrity at the bottom of the composite slab were enhanced to a certain extent， and the mechanical properties of the composite slab were improved. The reinforcement ratio and anchorage length of the additional rebars set at the composite surface of the splicing joint had a significant impact on the mechanical properties of the composite slab. The specimens with increased groove depth exhibited relatively outstanding bearing capacity and deformation performance， with good ductility. During the loading process， the restraining effect of the fiber composite materials on the bottom of the slab increased the cracking load of the composite slab， enhanced the stress transfer on both sides of the splicing joint at the bottom of the slab， reduced the degree of "deformation concentration" at the slab joint， and improved the stiffness and ductility of the composite slab．