For　the　pile　foundation　subjected　to　both　horizontal　and　vertical　loads,　the　horizontal　and　vertical　bearing　capacities　are　often　calculated　separately　according　to　existing　methods,　and　the　influence　of　the　vertical　loads　on　the　horizontal　bearing　capacity　of　the　pile　is　not　considered.　Several　model　tests　were　carried　out　for　the　horizontal　loaded　pile　to　study　the　horizontal　bearing　behavior　of　pile　under　the　action　of　existing　vertical　load　in　sandy　foundation.　In　order　to　avoid　imposing　additional　constraints　on　the　pile　top　under　vertical　loads,　the　selfdesigned　test　loading　device　was　developed　for　vertical　loading,　and　the　thin　film　pressure　sensor　was　used　to　accurately　measure　the　horizontal　soil　resistance.　The　test　results　show　that:　in　sandy　soil　foundation,　vertical　loads　applied　in　advance　reduces　the　horizontal　displacement　and　bending　moment　of　horizontal　loaded　pile　in　some　segments.　The　maximum　value　of　horizontal　soil　resistance　first　increases　and　then　decreases　with　the　increase　of　existing　vertical　load.　The　horizontal　bearing　behavior　of　the　small-diameter　preformed　pile　can　be　improved　by　the　vertical　load　in　sandy　soil　foundation　when　the　horizontal　displacement　is　small.