Abstract: Configuration of the solar-assisted heat pump with an innovative truncated-cone-type evaporator was designed. Mathematical models for parts of every system were set up. The results showed that when the average absorbance of solar radiation of a solar-assisted heat pump with a truncated-cone-type evaporator was 7.2 MJ, the coefficient of performance(COP) of the system was 3.1 under poor solar radiation in December in Kunming, China. When the system absorbed 15.6 MJ of solar radiation, the system’s COP could reach 3.8. The results indicate that the solar-assisted heat pump with a truncated-cone-type evaporator has high heating performance and can meet the demands of water supply.