According to one three-story RC frame structure, the results of time-history analysis of using re-centring SMA damper to seismic retrofitting are introduced in detail. Damping effect of dampers is studied by index such as floor displacement, story drift, story shear force, energy dissipation, etc., and optimal layout of dampers is also discussed. The analysis results indicate that floor displacement and story drift are decreased greatly after strengthening, and story shear force is controlled to some extent with good effect. The damper dissipates most of the total energy inputting into structure and also has good ability to re-centring. The damper can obtain good energy dissipation when arranged at the maximum story drift, and less energy dissipation when arranged at the smaller story drift.