The　discharged　flow　characteristic　from　an　unshrouded　centrifugal　impeller　with　splitter　blades　is　experimentally　investigated.　The　effects　of　the　main　blade　and　the　splitter　blade　on　the　unsteady　flow　quantities　are　analyzed.　An　X-type　hot-film　anemometry　is　used　to　measure　the　flow　quantities　at　the　impeller　outlet　and　diffuser　inlet　in　three　spanwise　positions.　The　result　shows　that　the　difference　between　the　splitter　and　main　blade　effects　on　flow　becomes　most　significant　at　the　mid-span　position.　At　the　impeller　outlet　near　the　main　blade　wake　region,　the　radial　velocity　reduces　by　62%,　the　tangential　velocity　increases　by　2%,　and　the　absolute　flow　angle　decreases　by　about　8　degrees,　comparing　with　that　near　the　splitter　blade　wake　region.　At　the　diffuser　inlet,　the　difference　between　the　splitter　and　the　main　blade　wake　regions　is　still　visible　though　it　has　been　weakened.　The　base　frequency　of　the　unsteady　flow　is　a　main　blade　or　a　splitter　blade　passing　frequency.　The　base　and　second　harmonics　exert　dominating　effects　on　the　unsteady　flow.　Reynolds　stress　levels　in　the　discharged　flow　from　the　main　blade　are　higher　than　that　from　the　splitter　blade.　Especially　in　the　mid-span　region,　the　Reynolds　stress　difference　reaches　to　68%.　The　absolute　outflow　angle　changes　more　than　10　degrees　in　the　spanwise,　which　indicates　that　separating　or　rushing　loss　may　be　produced　in　the　present　two-dimensional　vaned　diffuser,　so　a　three-dimensional　vaned　diffuser　seems　to　become　necessary.