This paper presents a prefabricated connection for the structure of RC flat slab to square steel tube column. A gap was left between the square steel tube column and RC flat slab, and it was connected by the I-steel cantilever beams aiming at enhancing the ductility and energy dissipation. Test investigations on punching behavior for the prefabricated connection between RC flat slab and square steel tube column and hysteretic behavior for the frame connected by the prefabricated connection were conducted. The failure modes and load-corresponding displacement curves for the punching shear and cyclic loading tests are presented. Strength, stiffness, ductility and energy absorption are evaluated based on the results of tests. The test findings indicated that the prefabricated flat slab connection exhibits a satisfactory punching shear behavior. And the frame with the prefabricated slab column connections also exhibits a satisfactory seismic behavior. The design considerations with the punching shear strength and the RC flat slab effective width equal to a moment frame beam are presented and validated. It is noted that the I-steel cantilever beam effectively improves the punching capacity and protects the RC flat slab and square steel tube column under the cyclic loading, and the earthquake-resilience is realized.