The　interfacial　bond　region　between　matrix　and　fibers　is　a　non-negligible　weak　link　that　can　significantly　affect　the　mechanical　properties　of　manufactured　sand-based　ultra-high-performance　concrete　(UHPMC).　This　study　investigates　the　interfacial　bond　characteristics　between　steel　fiber-UHPMC　matrix　using　single-fiber　pullout　tests.　Four　variable　parameters　were　considered:　manufactured　sand　(MS)　replacement　ratio,　stone　powder　content,　fiber　embedment　length,　and　steel　fiber　geometry.　Additionally,　the　microstructure　of　the　steel　fiber-UHPMC　matrix　interface　was　evaluated　using　backscattered　electron　microscopy　(BSEM)　and　scanning　electron　microscopy　(SEM).　The　results　indicate　that　two　typical　failure　modes　including　fiber　pullout　slip　failure　(in　straight　and　hooked-end　fibers)　and　fiber　rupture　failure　(in　corrugated　fibers)　were　observed.　The　analysis　of　interfacial　evaluation　indicators　shows　that　increasing　the　MS　replacement　ratio　from　25　%　to　100　%　results　in　a　decreasing　trend　in　peak　load,　peak　tensile　stress,　and　energy　consumption.　Peak　bond　strength　decreases　with　increasing　embedment　length.　With　the　increase　in　stone　powder　content,　the　peak　load,　peak　bond　stress,　and　energy　consumption　increase　initially　and　then　decrease.　Additionally,　the　interfacial　failure　mechanisms　between　straight/hooked-end　steel　fibers　and　the　UHPMC　matrix　were　further　elucidated　through　bond-slip　behavior　characterization　and　microstructure　analysis.　Finally,　a　design-oriented　bond-slip　model　was　developed　to　predict　the　interfacial　pull-out　behavior　of　steel　fiber　-UHPMC　matrix,　showing　favorable　agreement　between　predicted　and　test　results.　These　findings　contribute　to　understanding　the　interfacial　pullout　behavior　of　steel　fibers-UHPMC　matrix,　providing　data　reference　for　the　performance　optimization　of　UHPMC.　©　2024　Elsevier　Ltd