Thinning is an effective measure that can improve forest soil water conditions by increasing rainwater input and reducing interception losses. Many more studies focused on the effect of overstorey canopy on rainfall partitioning in thinned forests, while the role of understorey vegetation on rainfall partitioning after thinning has been inadequately quantified. In this study, 6 plots with different thinning intensities in Robinia pseudoacacia plantations on the Loess Plateau of China were set up, i.e., 0% (T0 %, nonthinning), 35 % (T35 %, light), 45 % (T45 %, medium), 55% (T55 %, moderate), 65 % (T65 %, heavy) and 80 % (T80 %, extremely heavy). Rainfall partitioning during the growing seasons of 2022-2023 and the vegetation characteristics of each plot were monitored to disentangle the effects of overstorey and understorey on rainfall partitioning under multiple thinning intensities. The results revealed that the overstorey canopy interception (CI) ranged from 11.00% to 15.28%, which was significantly less than the understorey interception (UI) with 42.14 % similar to 69.38 % in the different thinning intensity plots. The throughfall (TF) percentage and the stemflow (SF) percentage ranged 76.16% similar to 85.03% and 2.47% similar to 8.55%. TF, UI and total interception loss (I) generally increased with increasing thinning intensity, while both SF and CI showed a decreasing trend with increasing thinning intensity. Furthermore, rainfall characteristics affected rainfall partitioning. For the T0 %, T35 %, T45 %, T55 %, T65 % and T80 % plots, the threshold rainfall required for TF was 1.45, 0.29, 1.29, 0.62, 0.34 and 0.57 mm, and the threshold rainfall required for SF was 5.19, 4.89, 3.72, 4.34, 3.66 and 5.20 mm, respectively. Moreover, the characteristics of Robinia pseudoacacia plantations such as stand density, tree coverage and diameter at breast height determined overstorey rainfall partitioning (TF, SF and CI) among the varied thinning intensities plots. Among all the characteristics of understorey vegetation, the plant density and species abundance were the main factors that dominated the difference in UI of the 6 plots. Our concluded that while thinning increased TF, it resulted in an increase in UI due to the effects of understory vegetation after thinning. Therefore, our need to emphasize rainfall partitioning in the understory in the future. Our results contributed to the understanding of the relationship between thinning intensity and rainfall partitioning, thus benefiting the assessment of the effects of forest management on hydrological processes.