Abstract:Hydrological effects of coniferous and broadleaved mixed forest ecosystem in Dinghushan were studied from August 2002 to July 2003. The total precipitation during this period was 1 690 mm, of which the net precipitation under canopy was 1 212.7 mm, accounting for 72% of the total. The amounts of throughfall and stemflow were 1 125.3 mm and 87.4 mm, respectively, accounting for 66.6% and 5.2% of the total precipitation, respectively. Canopy interception was 447.3 mm, with an interception rate of 28.2%. The surface runoff was 621 mm (about 3.7％ oftotal precipitation)．It was shown that the amount of canopy interception increased with the increasing of precipitation，but having various tendency for different precipitation intensity classes． However, the critical canopy interception for precipitation event was about 25 mm． Throughfall and stemflow were linearly related to the precipitation．The surface runoff was also linearly related to precipitation when the daily precipitation was ≤ 30 mm， but nonlinearly related to precipitation at >30 mm． Compared with monsoon evergreen broadleaved forest or pure coniferOLlS forest，the coniferous an d broadleaved mixed forest had a greater hydro-ecological effect on decreasing surface runofr and water and soil conservation.