Ejector　can　utilize　high　pressure　energy　from　liquid　mechanism,　it　can　be　used　in　heat　pump　system　coupled　with　economized　vapor　injection　(EVI)　scroll　compressor.　When　running　under　low　temperature　conditions,　the　performance　of　the　EVI　system　with　ejector　can　be　improved　further.　In　this　paper,　the　design　method　of　the　heat　pump　system　with　ejector　is　presented,　and　the　process　for　designing　the　heat　pump　with　ejector　(EVIe)　was　summarized.　One　prototype　heat　pump　was　designed　under　the　condition　of　the　evaporation　temperature　of　-20　degrees　C,　and　an　experimental　setup　was　established　to　test　the　prototype.　The　measured　results　demonstrated　that　the　heating　EER(energy　efficiency　ratio)　of　the　EVIe　could　reach　about　4%　higher　than　that　of　the　system　without　the　ejector　when　the　heating　capacity　remained　nearly　constant.　The　design　method　is　helpful　to　development　of　a　heat　pump　system　coupled　with　scroll　compressor　and　ejector.