Although　the　performances　of　water-type　photovoltaic/thermal　collectors　are　significantly　impacted　by　mass　flow　rates,　they　are　commonly　studied　only　with　low　mass　flow　rate　less　than　0.09　kg/s.　This　paper　has　evaluated　both　electrical　and　thermal　performances　of　a　photovoltaic/thermal　water　collector　impacted　on　a　high　mass　flow　rate　more　than　0.25　kg/s.　The　influence　on　changed　water　volumes　(70-100　L),　coolant　mass　flow　rates　(0.005-0.25　kg/s)　and　installation　angles　(15-40　degrees)　are　also　investigated　to　identify　an　optimal　condition　for　the　PV/T　collector.　The　results　show　that　the　temperature　of　PV/T　collector　decreases　with　the　increasing　mass　flow　rate,　while　the　output　power　increases.　Interestingly,　both　of　them　varies　in　the　opposite　direction　when　the　mass　flow　rate　more　than　0.15　kg/s.　Furthermore,　the　temperature　difference　and　electrical　efficiency　of　the　PV/T　collector　are　rarely　affected　by　the　water　volume　and　installation　angle,　which　apparently　impact　on　the　thermal　efficiency.　In　addition,　the　electrical　energy　increment　and　thermal　efficiency　of　the　PV/T　collector　are　11%　and　57%,　respectively.　It　can　clearly　be　seen　that　the　PV/T　collector　processing　with　a　sheet-tube　structure　exhibited　the　highest　performance　at　the　coolant　mass　flow　rate　of　0.15　kg/s,　appending　with　a　water　volume　of　100　L,　and　installation　angle　of　25　degrees.