Abstract: In order to clarify the water resource conservation function of forest vegetation, using Pinus tabuliformis pure forest, Larix principis-rupprechtii pure forest, Platycladus orientalis pure forest, Pinus sylvestris var. mongolica pure forest, Quercus variabilis pure forest, Acer mono pure forest, the mixed forest of Pinus tabuliformis and Larix kaempferi, the mixed forest of Pinus tabuliformis and Larix principis-rupprechtii as the research objects in Jiulong Mountain in Beijing City, we investigated forest litters and soil water-holding capacity of eight kinds of forest stands. The results showed that the total litter storage capacity of the eight kinds of forest stands ranged from 8.87 to 47.87 t/ hm², and the storage capacity of undecomposed litter was higher than that of semi-decomposed litter. By analyzing the change rules of maximum water-holding capacity and the effective interception amount of undecomposed litter and semi-decomposed litter, we found that water-holding capacity of pure Pinus tabulaeformis forest was the highest as 36.46 t/ hm², followed by the pure Larix principis-rupprechtii forest (36.06 t/ hm²), while that of pure Platycladus orientalis forest was the lowest, 11.83 t/ hm². For the effective interception amount, the mixed forest of Pinus tabulaeformis and L. kaempferi had the maximum amount, 23.51 t/ hm², followed by the pure P. sylvestris var. mongolica forest, 19.85 t/ hm², and Platycladus orientalis pure forest had the minimum amount, 9.53 t/ hm². In terms of the forest litters and soil water conversion function of eight kinds of forest stands, we found that L. pure principis-rupprechtii forest and the mixed forest of Pinus tabulaeformis and L. principis-rupprechtii are much better than other forest stands. The water-holding capacity and immersion time of different litter layers are well correlated, and so are the water absorption rate of litter layers and immersion time. The average of soil bulk density of eight stands ranged from 0.89 to 1.41 g/ cm³, and the total soil porosity varied from 39.43% to 54.23%. By analyzing soil infiltration rate and infiltration time, we found that there is a power function relation between them with all values of R² greater than 0.90.