To　overcome　the　shortage　of　existing　rubber　bearings(RB),　a　new　type　of　isolator,　prestressed　rubber　bearing(PRB),　is　presented　in　this　paper,　which　was　invented　by　amplifying　appropriately　the　thickness　of　rubber　layers　in　conventional　laminated　rubber　isolator　combining　the　prestressing　principle.　Based　on　the　test　results,　the　nonlinear　analytical　model　of　isolated　structures　was　established.　The　analytical　formula　of　PRB＇s　horizontal　stiffness　was　derived　and　the　corresponding　computational　program　was　developed,　the　operating　principle　and　mechanical　properties　of　PRB　was　then　studied.　Through　the　time　history　analysis　of　isolated　structures,　the　isolation　capacity　of　PRBs　was　investigated.　The　results　show　that　PRB　is　bearing　with　variable　horizontal　stiffness.　It　not　only　has　horizontal　isolation　capacity　as　conventional　RBs　but　also　has　favorable　functions　of　horizontal　displacement　limitation(HDL),　and　the　higher　the　seismic　intensity　is,　the　better　the　HDL　property　is.