To　explore　the　shear　behavior　of　headed　studs　in　steel-UHPC　(ultra-high-performance　concrete)　composite　slab,　the　refine　finite　element　model　considering　the　effect　of　weld　collar　was　proposed.　Based　on　the　FE　model　verified　by　the　test　results,　the　influence　of　diameter　and　spacing　on　the　stud　shear　performance　was　discussed.　The　analytical　results　reveal　that　weld　collar　in　the　headed　stud　can　significantly　increase　the　shear　bearing　capacity　of　the　stud.　The　shear　bearing　capacity　of　the　stud　is　remarkably　influenced　by　diameter　and　spacing.　With　the　increase　of　the　diameter　and　shorten　spacing,　the　UHPC　slab　will　crack　or　could　even　represent　splitting　broken.　It　was　suggestion　that　the　minimum　spacing　of　13 mm　stud　should　greater　than　2.5　ds,　while　the　corresponding　results　were　3.5　ds　for　16 mm　and　19 mm　studs.　When　the　spacing　of　13 mm,　16 mm,　and　19 mm　studs　is　less　than　3.5　ds,　5.0　ds,　and　6.5　ds,　respectively,　the　group　stud　effect　should　be　considered　in　shear　bearing　capacity　of　the　studs,　which　may　be　taken　as　0.93.　©　2023,　The　Author(s),　under　exclusive　license　to　Springer　Nature　Singapore　Pte　Ltd.