A　simplified　model　for　a　single　pile　is　established　based　on　the　Pasternak　foundation　and　Euler　beam　models　considering　the　axial　second-order　effects　of　pile　shaft.　The　corresponding　analytical　solutions　are　derived　by　utilizing　the　differential　transformation　methods　and　the　double-shear　theory　as　well　as　the　pile-soil　continuity　conditions.　Then,　considering　the　dynamic　displacement　of　receiver　pile　II　caused　by　the　vibration　of　source　pile　I,　the　control　equation　for　horizontal　vibration　of　receiver　pile　II　is　established,　and　the　analytical　solutions　for　the　response　of　receiver　pile　II　are　obtained.　According　to　the　definition　of　dynamic　interaction　factor,　the　pile-pile　horizontal　dynamic　interaction　factor　is　further　obtained.　Finally,　the　superposition　principle　is　used　to　solve　the　horizontal　dynamic　impedance　of　pile　groups,　and　its　rationality　is　verified　by　comparing　with　the　existing　analytical　solutions.　On　this　basis,　the　influences　of　soil　shear　coefficient,　pile　type,　pile　to　diameter　ratio　and　axial　feature　parameters　on　the　horizontal　impedance　of　pile　groups　are　discussed　through　the　parametric　analysis,　and　the　distribution　of　the　reaction　force　at　the　top　of　the　pile　and　the　distribution　of　the　internal　force　of　the　pile　body　are　discussed.　It　may　provide　theoretical　guidance　and　reference　for　the　design　of　pile　groups　in　practical　engineering.　©　2023　Chinese　Society　of　Civil　Engineering.　All　rights　reserved.