Based　on　the　theory　of　Biot＇s　two-phase　medium　and　Novak＇s　thin　layer,　a　coupled　mechanical　model　of　pipe　pile　and　radially　inhomogeneous　saturated　soil　is　established　by　comprehensively　taking　into　account　the　saturated　surrounding　soil＇s　construction　disturbance　effect　and　the　influence　of　the　pipe　pile＇s　saturated　inner　soil.　First,　the　displacements　and　horizontal　impedances　of　the　surrounding　and　inner　soil　are　derived　using　the　potential　function,　Laplace　transformation　and　variable　separation　methods.　Second,　the　analytical　solution　for　the　hor-izontal　impedance　of　pile　head　is　obtained　by　combining　the　conditions　of　the　displacement　continuity　and　stress　equilibrium　on　the　soil-pile　interface.　Finally,　the　obtained　solution　for　the　pile　head＇s　horizontal　impedance　is　reduced　to　validate　the　rationality　of　the　proposed　solution　by　making　comparisons　with　existing　solutions.　On　this　basis,　a　detailed　parametric　analysis　is　given　to　explore　the　influence　of　the　pile　parameters　and　construction　disturbance　effect　on　the　horizontal　vibration　characteristics　of　pipe　pile.