[Objective] Forests are important sources of water conservation and are key areas for soil and water conservation. The transformation of natural forests into secondary forests or plantations has become a common development model in today's society, especially in regions with high resource demands and land pressure. However, the impact of forest type conversion on soil hydrophysical characteristics has not been comprehensively studied. This study aims to investigate the effects of forest type conversion on the hydrophysical characteristics of forest soils. [Methods] The study compares the effects of forest type conversion on porosity, permeability, and soil matric potential, using subtropical natural evergreen broad-leaved forests and the secondary forests, Castanopsis carlesii artificial forests, and Cunninghamia lanceolata artificial forests derived from them as research subjects. [Results] (1) after forest type conversion, the total soil porosity in the lower soil layer of secondary forests significantly increased by 5.43% compared to natural forests, The soil matric potential also significantly increased in dry season Cunninghamia lanceolata, by 5.01 kPa compared to natural forests. But the variation of soil permeability in different forest types is not significant; (2) in the 0-40 cm soil layer of the four forest types, soil particles are mainly dominated by sand particles, but only clay particles show a significant correlation with total soil porosity, and soil particle composition is not the controlling factor for soil water-holding indicators under forest type conversion; (3) the main controlling factors for soil water-holding indicators are soil bulk density and soil moisture, with significant correlations between soil bulk density and each water-holding indicator, while forest conversion leads to changes in soil bulk density and soil moisture, thereby causing changes in soil water-holding performance. [Conclusion] forest type conversion has a significant impact on the hydrophysical parameters of subtropical region soils, with the conversion from natural forests to secondary forests being beneficial for water conservation or soil retention, and conversion to Cunninghamia lanceolata artificial forests requiring soil amelioration measures to optimize their water retention and permeability. These research results provide a certain theoretical basis and data support for the sustainable management of subtropical forests and water conservation.