This paper analysis on the design and the test of an air-conditioner hot water combined unit using environmental friendly refrigerant R407C. Firstly the research status of the system is elaborated for air-source heat pump water heater simply. Then the principle and structure are described on an air-conditioner heat pump followed by a water heater at different running modes and different operation conditions. The hot water experiments of the unit in three seasons have been tested and researched in a multi-functional environmental chamber. Some analysis of the unit’s thermodynamic performance is carried out from the test data for improving such kind of machine afterward.