Abstract: The research and application of particle damper in civil engineering is simply in a theoretical and experimental stage because of the high nonlinear characteristics and complex factors, and no more mature and reliable theory has been formed to guide the design and application in actual civil engineering. When the damping particles are not accumulated, considering the collision process and friction effect between particles and chamber, a mechanical model of particle damper-SDOF system is constructed. The analytical solution of the displacement response of the theoretical model under harmonic excitation is obtained. The mechanical model could fully reflect the collision and non-collision process of particle dampers, and the phase trajectories could reflect the complex nonlinear characteristics of particle dampers. The rationality of the model and the correctness of the analytical results are proved by the verification of the hypothesis of the particle damper and the electromagnetic shaking table test of a single steel frame under simple harmonic excitation. Finally, the parameters of the particle dampers are analyzed in terms of particle size, excitation amplitude, excitation frequency and damping particle motion gap. Moreover, compared with the existing model of impact dampers, the results show that the mechanical model is more reasonable for evaluating the damping performance of particle damper.