Abstract: A new type of structural measure was put forward to improve the mechanical property of the flat-fell seam in two-way concrete composite floor． Monotonic tests were conducted on a composite slab strip，a composite slab strip with the flat-fell seam but no enhancing measures and a composite slab strip with enhancing measures on the flat-fell seam． The test results showed that lamination tears phenomenon was easily occurred on untreated rough surface when the joints in the composite slabs were not enhanced． After the crack-resisting steel bar was set on the joint，the limit bearing capacity of the slab strip would be greatly increased，but its effect on the short-period stiffness after cracking was little． The element analysis by ABAQUS 6. 11 program was conducted and the results between test and analysis were close; the impact of in the number of joints on the specimen's mechanical performance was also studied，which provided a basis for the further investigation of concrete superposed floor slabs．