Abstract: In this study, a total of 30 water samples (15 samples in each season) in Le’an River (Poyang Lake Basin, Jiangxi Province, China) were collected in December 2016 (dry season) and July 2017 (wet season) separately. Twenty-two physicochemical characteristics were analyzed, those included major ions, nutrients, and dissolved heavy metals, etc. Multivariate Statistical Analysis was used to analyze the hydrochemical characteristics and influencing factors. The results indicated that hydro-chemical types were different in three sections of the Le’an River, those were  HCO₃-Ca type in the upstream, SO₄-Mg-Ca type in the midstream, and SO₄-Ca-Na type in the downstream. The water chemical ions in the upstream were controlled by natural weathering of rock, while those in the midstream and downstream were most affected by anthropogenic activities. The concentrations of nutrients in the midstream and downstream water were higher than those from upstream water, while those nutrients had no significant differences between the midstream and downstream water. Additionally, the concentrations of nutrients in the dry season were higher than those in the wet season, and the concentrations of NH4⁺-N and TP in several water samples were higher than China's surface water Ⅲ quality standards. No significant difference of the dissolved heavy metals concentrations was observed between the midstream and the downstream waters. The main influencing factors of hydrochemical characteristic in the Le’an River were as follows: NH4⁺-N and Cl^- were affected by urban sewage; Cr, Cu, Zn, Fe, Pb and SO₄^2- were mainly attributed to industrial and mineral activities; NO^3- -N were affected by urban sewage, agriculture and mining activities jointly. The influencing factors of TP were complex in the wet season, which may be affected by soil soluble organic matter and agricultural fertilization, and in the dry season, the urban sewage was the main factor of TP. The results in this study could provide reference for the Poyang Lake Basin environmental protection.