Abstract: Based on the concept of damage control, a new floor-by-floor assembled beam-through steel frame system with curved knee braces and column end slip friction joints is proposed. Under seismic loading, the curved knee brace acting as the first "fuse" of the structure dissipates energy through plastic deformation. Then, the friction joints are employed as the second "fuse", which can avoid plastic damage of main members including beams and columns, and can realize a "stable, progressive and controllable" damage sequence of the structure under seismic loading. Two 1/2 scaled single-story steel frame specimens were designed and fabricated, the first of which is a steel frame specimen with a Cover-Plates Slip Friction Joint (CPSFJ) at the column base and an L-shaped Connector Slip Friction Joint (LCSFJ) at the column top, and the second specimen has curved knee braces at the top of the column on the basis of the first specimen. Quasi-static cyclic loading tests were conducted, and the results show that the configuration of slip friction joints at the column ends can effectively reduce plastic damage of the main structure and realize low damage of the frame structure. The steel frame specimen with curved knee braces has higher initial stiffness, bearing capacity and better energy dissipation than the one without curved knee braces, and plasticity of the curved knee braces initiates before the joints rotate during the loading process, and the plastic damage is mainly concentrated on the curved knee braces, CPSFJ cover plates and LCSFJ connectors, while the main members such as beams and columns are not damaged. The frames with these joints could be repaired quickly after the earthquake.