In this paper,first,the superelastic property of a domestic NiTi wire being 1mm in diameter was tested,and excellent superelasticity of the wire at room temperature was revealed. Then,by taking the wire as the material,a novel self-centering SMA ( Shape Memory Alloy) damper was proposed,with its structure and working principle being also introduced. Moreover,a double-flag hysteretic curve of the damper was found from the simulation with Matlab. Finally,a dynamic time-history analysis of a one-story steel frame fixed with the SMA damper was carried out, The results indicate that the proposed SMA damper effectively suppresses structural displacement response by 52% and controls the structural acceleration response to a certain degree.