Firstly, the super-elastic deformation behavior of shape memory alloy was studied through material test, and its stress-strain curves were equivalent to multi-linear model to obtain its calculation parameters. Then, a new enhanced energy dissipation SMA damper was proposed, with its structure, working principle, design methods, and restoring force model also being introduced and elaborated. Finally, a total of three analytical models were established including a conventional steel frame, a steel frame setting diagonal SMA cables and a steel frame installing new SMA damper. Through the seismic time-history analysis, the seismic performance of these three models was comprehensively investigated. The results show that the hysteresis loop of the new SMA damper is full and the new SMA damper performs perfect energy dissipation capability. Moreover, the proposed SMA damper effectively suppresses structural displacement response and inter-story drift angle response under rare earthquakes.