This study aims to explore the spatio-temporal variations of water chemistry in Nanchang section of the Ganjiang River and the influence of Nanchang city on the chemical feature. Water samples were collected from April 2015 to March 2016  monthly at five sites in this section. The distribution pattern and its influencing factors of chemical ions(HCO-3, Cl-, SO2-4, NO-3, K+, Na+, Ca2+, Mg2+ and NH+4), heavy metal elements(Cr, Mn, Fe, Ni, Cu, Cd, Sb and Pb), dissolved organic carbon(DOC) and total phosphorus(TP) were screened. The results showed that: 1. The water quality of Nanchang section were within the standard limits for surface water sources and the chemical type of water was HCO3-Ca. The variations of HCO-3, Cl-, SO2-4, NO-3, K+, Na+, Ca2+, Mg2+, NH+4, Mn and DOC concentration were significantly related to the flow, while variations of Cr, Fe, Ni, Cu, Cd, Sb, Pb and TP concentration were not significantly related to the flow. 2. The pollution status of the Nanchang section was as the follows: The south branch had the highest pollution level, followed by the north branch, the middle branch, water area in the urban center and the upstream had similar lower pollution level. Concentrations of TP, Cr, Ni, Cu, Sb and Pb were significantly higher in the south branch than in the other area. Concentration of Mn was significantly higher in the north branch than in the other waterbodies. 3.Concentrations of TP, Ni, Cu and Pb were significantly increased because of the influence of the urban area; concentrations of DOC and Cd were decreased as the river flowing through the urban area, then increased at the suburban agricultural area; the urban area of Nanchang did not significantly affect oncentrations of HCO-3, Cl-, NO-3, SO2-4, Na+, K+, Mg2+, Ca2+, NH+4, Cr, Fe, Mn and Sb.

Key words：Gangjiang River; Nanchang city; water chemistry; spatiotemporal variation