Abstract:Heat balance in lower-subtropical hillslope ecosystem in Heshan Experiment Centre, Guangdong Province, was measured. The results indicated that the total evapotranspiration heat flux and the sensible heat flux were 74.7% and 21.2% of the net radiation, respectively. There was less heat storage in the soil and vegetation. Although the amount of gross solar radiation and precipitation was suffcient, the water condition did not match with the heat condition in several months, which decreased the productivity of vegetation.