This　study　investigates　the　shear　fracture　behaviors　in　ultra-high-performance　concrete　(UHPC)　under　direct　shear　conditions　using　Z-shaped　specimens　and　acoustic　emission　(AE)　monitoring.　The　effect　of　steel　fiber　(SSF)　contents　(1%,　2%,　2.5%,　and　3%)　on　the　failure　process　and　the　relative　slip　of　cracks　at　different　loading　stages　were　measured　and　evaluated.　The　results　indicate　that　increasing　the　SSF　content　significantly　enhances　the　ultimate　shear　stress　and　ductility,　effectively　limits　crack　propagation　and　formation,　and　reduces　the　extent　of　damage　for　UHPC.　During　the　failure　process,　an　increase　in　the　SSF　content　results　in　higher　cumulative　AE　energy　and　a　tendency　for　the　peak　frequency　to　shift　towards　the　low-frequency　range.　Additionally,　increasing　the　SSF　content　expands　the　range　of　wavelet　entropy　values　and　delays　the　occurrence　of　wavelet　entropy.　Due　to　the　reinforcement　effects　of　SSF,　the　primary　crack　type　evolved　from　shear　to　tensile　during　the　failure　process.