A　steel-ultra　high　performance　concrete　(UHPC)　composite　deck　has　good　fatigue　performance　while　the　thin　UHPC　slab　leaves　a　very　limited　space　for　the　connector　configuration.　This　is　actually　crucial　to　achieve　the　composite　action.　Current　literatures　concerning　the　short　stud　behavior　are　still　limited　for　a　general　mechanism　understanding.　Therefore,　a　series　of　push-tests　containing　15　specimens　were　conducted　for　investigating　the　mechanical　behavior　of　short　studs　with　various　diameters　and　lengths　in　UHPC　composite　deck.　And　a　parametric　FEM　analysis　with　nonlinear　material　constitutions　was　conducted　as　well　for　the　bearing　performance　understanding.　The　push-out　tests　showed　the　shear　fracture　near　stud　roots　is　the　leading　dominant　failure　mode,　and　a　longer　stud　length　might　introduce　a　higher　percentage　of　stud　shank　bending　deformation.　It　explained　longer　stud　length　could　be　helpful　to　improve　the　shear　strength　of　stud　in　UHPC.　Meanwhile,　the　shear　stiffness　of　the　push-out　specimens　were　all　increased　with　a　larger　stud　diameter　or　length.　On　the　other　side,　the　analysis　results　showed　that　a　pull-out　failure　could　happen　when　the　stud　length　was　less　than　25　mm　in　UHPC　and　the　failure　mode　of　stud　could　also　be　affected　by　the　concrete　strength.　In　addition　to　the　tests　and　analysis,　the　safety　redundancies　of　strength　evaluations　of　short　stud　in　UHPC　based　on　several　civil　codes　were　discussed　in　terms　of　the　comparison　works.