In hot summer and cold winter areas, air source heat pump is a good choice for heating and cooling. Combination of floor heating and air source heating pump is a promising solution for space heating in the middle of China. However, the air-source heat pump affected by the ambient air temperature and outlet water temperature and other factors. (1) Experimental testing of the air-source heat pump under various outdoor temperature was conducted； When the ambient temperature is -4°C with outlet water temperature near 55°C, the heat pump can operate normally and has the COP of 2.0. (2) The required floor heating supply water temperature under various outdoor temperatures is calculated, and the electricity consumption and average COP is calculated using BIN method for the whole heating season. The average seasonal COP is 3.41 for this case in Shanghai.