[Objective] The objective of this study is to analyze the mechanism of water conservation in Phyllostachy pubescens forest in the hilly areas of Southern Jiangsu Province, and reduce the influences of intensive bamboo management on soil and water loss . [Methods] ECH₂O soil moisture content detection system was used to measure the volumetric soil water content (VSWC) at four soil depths (10, 15, 40, 60 cm) in P. pubescens forest in Nanjing Tongshan forest farm. The observed VSWC data (from June 2012 to August 2013) was used to analyze the variability of VSWC under different precipitation intensity. The VSWC curve at different soil depths under different precipitation intensity was made, and lateral flow was proposed to analyze its response to different rainfall conditions (light, moderate and heavy rain). [Results] The VSWC at the depth of 10 and 15 cm changed consistently with the variation of rainfall. The peak value of soil moisture content in the soil depth of 40 and 60 cm was delayed by 0.5 to 1.5 h, The variation amplitude of VSWC decreased from the surface to 40 cm of soil depth under light rainfall condition. The variation amplitude of VSWC increased from the 15 to 60 cm of soil depth under moderate rain and heavy rain conditions, and this trend was more obvious under the heavy rainfall condition. The maximum lateral flow under light, moderate and heavy rainfall condition was 10.17, 60.26 and 95.92 mm, respectively. [Conclusion] As the increase of soil depth, the synchronicity between the VSWC and rainfall declined. Obvious differences in the amplitude of VSWC were existed among different soil layer with different rainfall intensity. Rainfall infiltration was unsaturated infiltration. Lateral flow existed in vertical plane under each rainfall, and they mainly concentrated at 40-60 cm soil depths, and influenced by soil structure and precipitation intensity.