Air-source　heat　pump　has　many　dominant　advantages　such　as　high　efficiency,　convenient　operation　and　no　pollution　to　the　environment,　so　it　has　been　widely　used　for　heating　in　China　in　the　winter.　The　recent　comprehensive　research　and　development　on　air-source　heat　pump　were　accomplished　by　Chinese　technologists　are　reviewed　in　this　paper.　The　two　important　research　achievements　are　then　described.　One　is　technological　retrofit　of　the　air-source　heat　pump　to　improve　its　reliability　and　heating　capacity　when　it　operates　in　low　ambient　temperature　environment,　and　the　another　is　the　advanced　defrosting　technique　to　improve　defrosting　efficiency　and　accuracy　in　defrosting.　These　achievements　are　very　helpful　to　develop　new　generation　products　of　the　air-source　heat　pump　with　independent　intellectual　property　of　China.