To make clear the influence of species composition and community structure on redistribution of rainfall and nutrient, three typical riparian forest, Larix kaempferi forest, Quercus mongolica forest, Acer ukurunduense forest were selected as objects of study in the mountain regions of eastern Liaoning Province from May to October 2014. The rainfall process and nutrients characteristics in atmospheric rainfall, throughfall and stemflow were analyzed. The results showed that during the research period, the total precipitation was 278.6 mm, and the throughfalls of Larix kaempferi forest, Quercus mongolica forest, Acer ukurunduense forest were 81.9%, 77.9% and 73.1% of total rainfall, respectively, and stemflow were 1.2%, 4.4% and 4.3%, respectively. The concentrations of NH₄⁺-N, Cl^-, NO₃^--N and total phosphorus (TP) in throughfall and stemflow were higher than those of atmospheric rainfall, and the concentrations and inputs of NH₄⁺-N, Cl^-, NO₃^--N and TP in different forest types were different significantly. The riparian forest with different species composition and community structure influenced rainfall distribution through the morphological and structure characteristics of community, and changed water physical and chemical properties through the physical, chemical and physiological characteristics of forest canopy gaps, resulting in the changes of the concentrations and inputs of NH₄⁺-N, Cl^-, NO₃^--N and TP variously combined with rainfall amount and intensity.