Rainfall partitioning by forests is one of the important processes in forest eco-hydrological and biogeochemical cycles. In this study, the characteristics and main influencing factors of rainfall partitioning of two typical forest types (Robinia pseudoacacia plantation and Quercus liaotungensis natural secondary forest) were investigated by field monitoring during the growing season in the loess hilly region. The results showed that during the experiment, the components of rainfall partitioning in R. pseudoacaciaplantation and Q. liaotungensis forest were in the order of throughfall (325.0 and 295.1 mm) > canopy interception (39.8 and 73.6 mm) >stemflow (25.8 and 21.9 mm), and throughfall rate (83.2% and 75.6%) > canopy interception rate (10.2% and 18.8%) >stemflow rate (6.6% and 5.6%). Rainfall amount was the key factor affecting rainfall partitioning. A highly significant linear relationship was observed between throughfall and stemflow and rainfall amount, while the relationship between canopy interception and rainfall amount exhibited a highly significant logarithmic function. A significant logarithmic relationship existed between throughfall rate and stemflow rate and rainfall amount, while a highly significant exponential relationship was found between canopy interception rate and rainfall amount. Throughfall processed when rainfall exceeded 1.0 and 1.3 mm for R. pseudoacacia plantation and Q. liaotungensis forest, respectively. Stemflow processed when rainfall exceeded 5.9 and 5.4 mm for R. pseudoacacia plantation and Q. liaotungensis forest, respectively. The throughfall and stemflow generated by R. pseudoacaciaplantation were larger than that of Q. liaotungensis forest,while the canopy interception was smaller than that of Q. liaotungensis forest. This study provides basic data for the research of eco-hydrological processes in the loess hilly region, and has guiding significance for the selection of vegetation types in the process of vegetation restoration in this area.