In　this　paper,　the　performance　of　several　different　kinds　of　Rake　receivers　for　a　BPSK　Ultra　Wideband　system　is　studied　with　inter-symbol　interference　in　a　realistic　channel　model　that　is　accepted　by　the　IEEE　802.15.3a　task　group.　We　evaluate　the　bit　error　rate(BER)　of　several　different　kinds　of　Rake　combining　methods(including　SRAKE-MRC,　SRAKE-EGC,　PRAKE-MRC,　and　PRAKE-EGC)　under　two　typical　channel　conditions(0-4m　LOS(CM1)　and　0-4m　NLOS(CM2)).　We　show　that　under　the　same　number　of　fingers　and　data　transmission　rate,　SRAKE-MRC　achieves　the　best　BER　performance　among　all　kinds　of　RAKE　combining　methods　described　above,　and　BER　performance　is　not　very　sensitive　to　the　increase　of　finger　numbers　with　SRAKE　combining　method　while　the　case　is　quite　different　with　PRAKE　combining　method.　We　also　show　that　under　the　two　typical　channel　conditions,　there　is　always　a　limit　data　rate　(it　is　about　300Mbps　under　CM1,　and　100Mbps　under　CM2),　which　means　the　BER　performance　will　stay　at　a　fixed　level　(about　10(-1)　to　10(-2))　no　matter　how　many　fingers　we　employ.