Abstract: The seismic behavior of a steel implanted storey-adding frame and a steel implanted storey-adding frame strengthened with CFRP sheet for 1/3 scale model was investigated under low cycle reversed load． The failure characteristics，hysteresis properties，rigidity degeneracy，displacement ductility and energy dissipation capacity of the two specimens were compared． The test results revealed that the cement based inorganic anchoring material used in structural anchorage had good mechanical properties． The seismic behavior of steel storey-adding frames was favorable． After the steel implanted joint was reinforced by CFRP sheet，the failure mechanism of the storey-adding frame was turned from hybrid hinged failure into beam hinged failure，and the seismic behavior of the structure was significantly improved．