Unifying　the　cooling　capacity　measurement　result　has　a　fundamental　effect　on　energy　conservation　and　emission　reduction　in　air-conditioner　industry.　The　water-enthalpy　method　cooling　capacity　source　could　be　applied　in　the　calibration　of　cooling　capacity　measuring　apparatus;　it　could　supply　a　cooling　capacity　that　is　measurable　and　controllable.　In　this　research,　the　principle　of　the　water-enthalpy　method,　which　reduces　the　number　of　measuring　parameters,　was　illustrated　first.　Then,　the　physical　structure　of　the　source　was　designed　and　developed,　and　the　source　was　experimentally　investigated　with　a　balanced　ambient　room-type　calorimeter.　The　experiment　results　show　that　the　maximum　relative　difference　of　cooling　capacity　between　the　source　and　the　calorimeter　is　less　than　±0.7%.　Finally,　the　uncertainty　evaluation　process　and　result　of　the　cooling　capacity　output　of　the　source　are　given　in　detail.　The　evaluation　results　show　that　the　repeatability　of　the　source　is　11.4　W;　as　the　cooling　capacity　increases　from　1　660.8　to　5　810.4　W,　the　combined　standard　uncertainty　increases　form　12.3　to　18.2　W,　and　the　relative　expanded　uncertainty　decreases　from　1.5%(k=2)　to　0.6%(k=2).　With　the　water-enthalpy　method　the　traceability　of　cooling　capacity　source　is　achieved　for　the　first　time　from　the　perspective　of　metrology,　the　cooling　capacity　could　be　traced　to　temperature,　pressure,　flow　rate　and　electric　power,　and　the　source　apparatus　could　be　used　as　standard　cooling　capacity　source　in　calibration.　©　2017,　Science　Press.　All　right　reserved.