In　order　to　study　the　longitudinal　vibration　characteristics　of　floating　piles　in　saturated　soil,　a　saturated　virtual　soil　pile　model　based　on　Biot＇s　wave　theory　was　proposed,　and　a　coupled　longitudinal　vibration　system　of　three-dimensional　saturated　layered　soil,　virtual　soil　piles　and　solid　piles　was　established.　The　analytical　solution　of　the　displacement　of　saturated　soil　was　derived　by　potential　function　method,　and　the　vertical　dynamic　impedance　at　the　pile　head　was　obtained　by　using　the　pile-soil　compatibility　conditions　and　the　transfer　method　of　impedance　function.　The　validity　of　the　obtained　solution　was　verified　by　degrading　to　existing　solutions,　and　parametric　analyses　were　performed　to　investigate　the　effects　of　the　parameters　of　the　saturated　soil　on　the　vibration　characteristics　at　the　pile　head.　The　results　show　that,　when　the　saturation　of　soil　layers　beneath　the　pile　toe　is　remarkable　and　the　drainage　is　poor,　the　saturated　virtual　soil　pile　model　and　the　relevant　analytical　solution　is　more　suitable　to　analyze　the　longitudinal　vibration　characteristics　of　floating　piles.　The　longitudinal　interlayer　of　surrounding　soil　has　obvious　effect　on　the　amplitude　of　the　dynamic　impedance　at　the　pile　head,　but　the　effect　of　longitudinal　interlayer　of　soil　beneath　the　pile　toe　on　the　dynamic　impedance　at　the　pile　head　can　be　ignored.　The　porosity　of　saturated　surface　surrounding　soil　has　obvious　influence　only　on　the　resonance　amplitude　of　the　dynamic　impedance　at　the　pile　head,　while　the　porosity　of　saturated　soil　beneath　the　pile　toe　has　significant　effects　both　on　the　resonance　amplitude　and　the　resonance　frequency　of　the　dynamic　impedance　at　the　pile　head.　©　2019,　Science　Press.　All　right　reserved.