In this study, the steel damper system was proposed to improve the seismic performance of reinforced concrete(RC) frame with non-seismic details. The cyclic lateral loading test was performed to evaluate the capacity of the proposed steel damper system and RC frame. The test results of the proposed steel damper system showed that its hysteretic behavior was stable and the energy absorbtion capacity was excellent. The RC frame with non-seismic details showed brittle shear failure, while the frame with steel damper system was occurred a little damage. And the retrofitted frame with steel damper system showed better capacity of strength, stiffness and energy absorbtion. The shaking table test using seismic waves was performed to confirm the dynamic response characteristics of RC frame with steel damper system or not. The result of the shaking table test was similar to that of static loading test.