To evaluate the water conservation capacity of forests in the Mount Tumor Nature Reserve quantitatively, comprehensive water storage capacity method was used to investigate the canopy interception capacity (C), litter water-holding capacity (L), soil water storage capacity (S) of Picea schrenkiana forest ecosystems in the upper Tailan River, then a comprehensive evaluation of its water conservation function was made. The results showed that: ① In the four sample areas, the canopy interception capacity followed the order og the middle altitude spruce forest (29.94 mm) > higher altitude spruce forest (20.56 mm) > high altitude spruce forest (11.72 mm) > low altitude mixed?broad leaf-conifer?forest (5.84 mm), and the stem flow showed the opposite order. ② Except for the middle altitude spruce forest, the average?thickness of un-decomposed litter was thicker than that of the?intermediately decomposed layer. The high altitude spruce forest had the largest average volume of decomposed layer (79.32 t/hm2), while the middle altitude spruce forest had the largest intermediately decomposed layer (59.47 t/hm2). On the whole, the rank of the maximum water holding capacity was the middle altitude spruce forest (32.55 mm) > the high altitude spruce forest (31.05 mm) > the higher elevation spruce forest (30.78 mm) > the low altitude mixed?broad leaf-conifer?forest (12.84 mm). ③ Soil bulk density in the four sampled forests ranged from 0.73 to 1.06 g/cm3. Both the average soil porosity and water holding capacity of capillary pore in the 30-cm soil layer were in the order of the middle altitude spruce forest > the higher altitude spruce forest > the high altitude spruce forest > the low altitude mixed?broad leaf-conifer?forest. Overall, soil moisture content of natural forests increased with the increase of the altitude. The average water holding capacity of non-capillary pore in the 30-cm soil layer followed the order of the middle altitude spruce forest (37.6 mm) > the higher altitude spruce forest (30.7 mm) > the high altitude spruce forest (25.73 mm) > the low altitude mixed?broad leaf- conifer?forest (13.92 mm). ④ Comprehensive water conservation capacity of the forest ecosystems in the study area was bwteen 141.12 and 280.84 mm, with the low altitude mixed?broad leaf-conifer?forest and the middle altitude spruce forest having the smallest and largest water holding capacity, respectively. The soil layer contributed the most to water conservation, accounting for 77.75%-86.96%. Comprehensive effective water storage capacity was far less than the theoretical total capacity, but could work well in the water conservation function as well as water and soil conservation effect.