Given　the　extensive　utilization　of　composite　structures　of　ultra-high　performance　concrete　(UHPC)　and　normal　concrete　(NC)　in　engineering　applications,　there　has　been　a　growing　emphasis　on　studying　the　shear　failure　and　mechanical　properties　analysis　of　the　UHPC-NC　interface.　U-shaped　studs　assume　a　crucial　role　in　reinforcing　the　UHPC-NC　interface.　A　three-dimensional　finite　element　model　was　constructed　with　different　parameters　to　investigate　the　shear　failure　and　mechanical　properties　of　UHPC-NC　incorporating　U-shaped　studs.　The　failure　mode　and　the　influences　of　diameter,　internal　span,　stud　number　and　concrete　compressive　strength　on　the　shear　characteristics　of　the　UHPC-NC　interface　were　analyzed.　The　numerical　analysis　indicates　the　final　failure　mode　of　the　UHPC-NC　interface　with　U-shaped　stubs　is　the　fracture　of　the　U-shaped　stud.　The　diameter　and　internal　span　of　studs　influence　the　interface　shear　capacity,　while　interface　shear　capacity　is　not　sensitive　to　the　compressive　strength　of　UHPC　and　NC.　Moreover,　a　calculation　formula　for　the　shear　capacity　of　the　UHPC-NC　interface　with　U-shaped　studs　was　proposed,　considering　the　influence　of　stud　diameter　and　internal　span.　An　exponential　function　is　recommended　for　predicting　the　interface　shear　slip　and　the　stiffness　corresponding　to　0.55　times　the　shear　capacity　is　adopted　as　the　elastic　shear　stiffness.　The　interface　shear　slip　model　and　the　expression　for　elastic　shear　stiffness　were　established,　providing　a　reference　for　approximate　calculation　without　experimental　data.　©　2024