The　quasi-two　stage　compression　air　source　heat　pump　(QTASHP)　is　still　restricted　in　use　in　severe　cold　region　due　to　the　excessive　discharge　temperature　caused　by　ultra-low　ambient　temperature.　To　promote　the　application　of　QTASHP　in　severe　cold　region,　a　novel　control　strategy　was　proposed,　and　it　was　used　in　a　test　rig　in　Harbin.　The　test　rig　adopted　a　scroll　compressor　with　vapor　injection,　and　its　technical　feasibility　was　investigated　through　supplying　heating　for　a　lab　in　the　whole　heating　season.　Then　based　on　experimental　results,　its　economic　and　environmental　benefits　were　analyzed.　Results　showed　that　QTASHP　could　run　smoothly　in　the　whole　heating　season,　and　its　highest　discharge　temperature　was　118.82　degrees　C　at　the　highest　compression　ratio　of　12.13.　This　indicated　the　proposed　control　strategy　could　solve　the　excessive　discharge　temperature　problem　effectively.　Apart　from　ultra-low　temperature,　low　temperature　frosting　was　also　a　main　challenge　for　QTASHP　in　severe　cold　region.　Besides,　comparing　with　central　heating　and　electric　boiler,　its　primary　energy　efficiency　increased　by　18.67%　and　140.54%,　while　pollutants/CO2　emission　decreased　by　15.41%　and　58.27%.　However,　its　economic　benefit　was　worse　than　central　heating　due　to　high　initial　investment,　while　far　better　than　electric　boiler.　(C)　2020　Elsevier　B.V.　All　rights　reserved.