The　distribution　of　fibers　and　the　fiber　bridging　affect　the　flexural　strength　and　energy　dissipation　of　ultra-highperformance　fiber　reinforced　concrete　(UHFRC)　members.　In　this　study,　an　analytical　model　to　predict　the　flexural　behavior　of　UHPFRC　was　developed　based　on　the　three-dimensional　random　distribution　of　fibers.　The　probability　distribution　model　of　the　fiber　orientation　was　developed　as　a　sine　function,　which　agreed　to　the　measured　probability　data　from　the　randomly　distributed　fiber　specimens.　The　number　of　fibers　at　the　fracture　surface　was　determined　addressing　the　effect　of　fiber　orientation.　Based　on　the　proposed　model,　the　method　to　predict　the　load-deflection　curve　of　UHPFRC　beam　was　suggested　addressing　the　fiber　bridging　stress　at　fracture　surface　and　tension　softening　effect.　For　verification,　the　four　points　flexural　tests　were　conducted　for　six　UHPFRC　beam　specimens.　The　test　results　showed　that　the　peak　flexural　strength　and　energy　dissipation　can　be　predicted　by　the　proposed　model.　Further,　the　proposed　model　was　applicable　to　predict　the　strength　and　deformation　capacity　of　existing　test　specimens.　Based　on　the　proposed　model,　the　aspect　ratio　of　fibers　to　prevent　the　brittle　failure　due　to　fiber　rupture　was　suggested　addressing　the　fiber　tensile　strength　and　bond　strength.