The　balanced　ambient　room　type　calorimeter　is　generally　used　as　the　cooling　capacity　measurement　standard　equipment　in　the　air　conditioner　industry.　However,　the　calibration　procedure　is　not　investigated.　In　this　study,　based　on　the　empty-load　situation　of　calorimeter,　the　calibration　model　is　proposed　in　order　to　restrain　the　error　of　heat　balance　caused　by　long-term　use.　Besides,　two　new　parameters,　which　are　background　value　of　indoor-side　and　outdoor-side,　are　presented　in　accordance　with　the　calibration　model.　Experiments　are　designed　to　obtain　these　two　parameters　and　three　heat　leakage　coefficients　of　partition　wall,　as　well　as　the　calibration　procedure　and　application　method　of　the　parameters　are　illustrated.　The　corrected　calorimeter　measures　ten　different　window　type　air　conditioners　in　one　year.　The　results　show　that　the　absolute　value　of　heat　balance　is　less　than　2%　in　the　cooling　capacity　range　of　2000W~4500W　and　1%　in　the　range　of　4500W~7000W.　©　2019　International　Institute　of　Refrigeration.　All　rights　reserved.