Regarding a pile and superstructure as a Timoshenko beam and a single degree of freedom spring-mass system, respectively, the horizontal vibration characteristic of the pile-liquefied soil-superstructure coupled system subjected to a vertical incident harmonic SH wave was investigated based on the Winkler model of the pile-soil interaction.  The boundary value problem of the single pile-liquefied soil-superstructure coupled system was established, in which the free-field displacement of the soil, translational and rotational inertia of the superstructure and the second order effect of the axial pressure of the pile are taken into consideration.  And the analytical solutions of the pile deformation and superstructure motion were derived.  The influences of the geometry and physics parameters on the displacement amplification factors and dynamic amplification factors at the pile top and of superstructure were examined numerically.  It is shown that there exists an evident resonance phenomenon in single pile-liquefied soil-superstructure system, and the influence of the soil free-field displacement on the displacement amplification factors of the pile top and superstructure is remarkable.  Furthermore, with the increase of the superstructure stiffness, fundamental frequency of the single pile-liquefied soil-superstructure system increases and the peak value of displacement amplification factors decrease.  At the same time, with the development of soil liquefaction degree, the fundamental frequency and dynamic amplification factors of the single pile-liquefied soil-superstructure system decrease.