Abstract: To solve the problems of heating intermittent and instability for household solar water heater, application of heat pump for evacuated tube solar water heater system can achieved auxiliary heat supply round-the-clock. Heating performance test and operation of the system were conducted and the temperature rise performance, heat preservation of the solar water heater system and the heating performance of heat pump were tested and analyzed in this paper. The result showed that when the solar radiation was less than 14 MJ/m2 , the system needed heating by air source heat pump, on this occasion, the system total coefficient of performance could reach 6.18.