For　security　reasons,　charged　mass　is　strictly　controlled　for　flammable　refrigerant　like　R290,　which　would　hamper　heating　capacity　under　low　temperature　conditions　in　winter.　This　paper　compared　thermo　physical　properties　and　cycle　performance　between　R290　and　R22.　Then　with　considering　the　thermodynamic　properties　of　R290,　a　study　was　done　on　the　feasibility　and　effects　of　different　heating　capacity　enhanced　technologies　applied　in　air-conditioning　using　R290.　It＇s　based　on　the　technology　analysis　that　the　heating　capacity　enhanced　of　heat　pump　air-conditioning.　Proposed　the　technology　that　could　improve　the　heating　capacity　of　R290　air-conditioning　efficiently.　It　could　provide　a　reference　for　the　study　and　development　of　heat　pump　air-conditioning　using　R290.