Based on the solar photovoltaic-thermal integrated system, we designed a dual-source, i.e., solar photovoltaic-thermal and air source, heat pump unit. The unit becomes solar assisted heat pump system when combined with solar photovoltaic thermal unit, which produces domestic hot water by air source and circulating water in the solar photovoltaic solar-thermal components (PV/T) and reduces circulating water temperature and solar photovoltaic panel temperature. We drew the conclusion by experiment that when the inflow water temperature is 20 ℃ on the evaporation side and the outflow hot water temperature is 50 ℃ under the rated conditions, the unit capacity is 2.855 kW for refrigeration and 3.594 kW for heating, and the COP is 3.6. When the unit operates in the water-water condition and water-air condition, the experiment result shows the dual-source heat pump unit has remarkable energy-saving compared with single air source heat pump when the photovoltaic-thermal solar heat is used for domestic hot water.