[Objective] The effects of rainfall characteristics, canopy structural characteristics and different management intensities on rainfall redistribution in Castanea mollissima forests were investigated, and the key regulatory processes of understory water input were revealed, in order to provide a scientific basis for coordinating the production and ecological functions of C. mollissima forests. [Methods] Taking typical C. mollissima forests in the mountainous area of southern Anhui Province as the study object, rainfall monitoring was conducted from June 5 to August 1, 2025 to analyze the rainfall redistribution process, water balance characteristics, and influencing factors in C. mollissima forests. [Results] ① The components of rainfall redistribution in C. mollissima forests were closely related to the rainfall outside the forest. The throughfall, stemflow and canopy interception all increased linearly with increasing rainfall. The throughfall rate and stemflow rate increased logarithmically with rainfall, canopy interception rate decreased logarithmically, and surface soil water content was positively correlated with rainfall.② Throughfall and stemflow in the heading-back pruned plots were lower than those in the unpruned plots, whereas surface soil water content was higher in the pruned plots.③ Throughfall(rate), stemflow(rate), canopy interception, and surface soil water content were all significantly positively correlated with rainfall, and surface soil water content was significantly negatively correlated with crown width and tree height. [Conclusion] Rainfall redistribution in C. mollissima forests is mainly driven by rainfall. Heading-back pruning can significantly reduce throughfall and stemflow and increase surface soil water content.