Due　to　the　low　temperatures,　the　heating　efficiency　of　air　source　heat　pump　systems　during　the　winter　is　very　low.　To　address　this　problem,　a　low-temperature　solar　hot　water　system　was　added　to　a　basic　air　source　heat　pump　system.　Several　parameters　were　tested　and　analyzed.　The　heat　collection　efficiency　of　the　solar　collector　was　analyzed　under　low-temperature　conditions.　The　factors　that　affect　the　performance　of　the　heat　pumps,　such　as　the　fluid　temperature,　pressure,　and　energy　savings,　were　analyzed　for　cases　where　the　solar　energy　auxiliary　heat　pump　and　the　air　source　heat　pump　are　used　independently.　The　optimal　heating　temperature　and　the　changes　in　the　fluid　temperature　were　determined.　The　influence　of　the　compression　ratio　and　the　coefficient　of　performance　(COP)　were　investigated　theoretically.　The　results　revealed　the　parameters　that　are　important　to　the　performance　of　the　system.　Several　measures　for　improving　the　COP　of　the　heat　pump　units　are　provided　for　other　applications　and　future　research.