Used the method of water-balance, the redistribution of rainfall by mixed forest in Huoditang area of Qinling mountain is studied. The results are as follows (1)Woods canopy 's interception of rainfall,runoff of woods stems and the rainfall under the woods are 126. 58, 11.69 and 588.2mm，which account for 17. 43, 11. 61 and 80. 96 percent of the total rainfall respectively during July to October in experimental area.Most of precipitation falls into forest by the rainfall under woods.(2)Dead leaves and branches under the woods intercept 85. 01mm rainfall, which account for 11. 75 percent of the total rainfall. They play important roles in retaining water.(3) Changing amplitude of water storage in woodland is 53.45mm. Woodland is very important for reducing the crest of runoff, adjusting runoff and shortening dry season.(4) The results of forest eco-system water-balance are that forest evapotranspiration is 521.01mm, the runoff is 155.24 mm，and the change of woodland soil water storage is+50. 09 mm. They make up 71.73, 21.37 and 6.9 percent of the total rainfall, 726. 34mm of the same period. Forest evaportranspiration is the most part of woods water output.