The　particle　damper　is　an　efficient　passive　control　device,　which　has　been　the　focus　of　extensive　research.　It　has　certain　applications　in　the　fields　of　machinery,　aviation,　and　aerospace,　and　is　currently　being　investigated　in　the　field　of　civil　engineering.　The　current　theoretical　model　of　the　particle　damper　is　based　on　observations　of　the　vibration　phenomena　of　particles　and　a　controlled　structure,　which　cannot　directly　reveal　its　damping　mechanism.　In　this　paper,　a　multiple　unidi-rectional　single-particle　damper　(MUSPD)　is　discussed.　Its　mechanical　model　is　established,　and　the　corresponding　numerical　simulation　method　is　proposed.　Both　the　rationality　and　feasibility　of　the　numerical　simulation　method　are　verified　using　a　shaking　table　test.　Secondly,　based　on　the　analysis　of　the　damping　mechanism　of　the　MUSPD,　the　collision　force　between　a　particle　and　the　controlled　structure　is　equivalent　to　an　impulse　force;　hence,　an　equivalent　mechanical　model　for　the　MUSPD　is　established　which　is　solved　analytically　in　the　frequency-time　domain.　Next,　based　on　the　equivalent　mechanical　model,　a　performance　optimization　method　for　the　MUSPD　under　dynamic　load　is　proposed.　Finally,　the　accuracy　of　the　equivalent　mechanical　model　and　the　performance　optimization　method,　along　with　the　effectiveness　of　the　latter,　are　verified　by　numerical　simulation　of　the　MUSPD.　The　results　indicate　that　the　MUSPD　has　a　fine　damping　effect,　and　its　numerical　simulation　method　is　reasonable　and　effective.　The　equivalent　me-chanical　model　of　the　MUSPD　can　directly　represent　its　damping　mechanism　and　has　high　ac-curacy,　and　the　performance　optimization　method　is　both　reasonable　and　feasible.