The shaking table test of a half-cycle negative stiffness friction damping device with negative stiffness characteristics is carried out. Taking a four-floor steel structure frame as the seismic reduction research object， the half-cycle negative stiffness fric? tion damping devices were arranged on the first and second floors of the steel structure frame respectively， and the seismic response of the structure under different ground motions was analyzed. The results show that the half-cycle negative stiffness friction damp? ing device can control the acceleration and displacement response of the structure， and better seismic reduction effect can be ob? tained if it is arranged on the position with large structural deformation.