Forest litter layer leads to redistribution of rainfall, which has more porosity than top soil, that is beneficial for retaining moisture, controlling surface evaporation and promoting the effect of infiltration. Litter-fall facilitates the capture and infiltration of rainwater into lower soil layers. Litter-fall protects soil aggregates from the impact of raindrops, preventing the release of clay and silt particles from plugging soil pores. Litter-fall can reduce the impact of raindrops, reduce the soil structure damage caused by the raindrop splash and soil erosion, prevent soil splash erosion, hysteresis, runoff, production flow time, and increase soil resistance. Litter-fall is considered as the main function of water conservation in the forest ecosystem, which plays a very good role in soil and water conservation and water conservation. Among different forest types with various forest canopies, under the wood or ground cover layer, litter-fall’s structure, composition, types, quantity and properties vary, which affect the forest hydrological function. Therefore, the study of the hydrological function of litter-fall on water cycle and water balance in the forest ecosystem is very useful and of great significance.