Groundwater quality is an important part of Poyang lake water ecological environment, it is significant to study the hydro-chemical characteristics, material mechanism and water pollution of groundwater.This paper analyzes the hydro-chemical characteristics and material source mechanism of groundwater in Xinjiang River basin by Gibbs graphic method, correlation analysis method and principal component factor analysis method. The result shows that precipitation is the main recharge source of groundwater, Ca2+, Na+, HCO3- are the dominant ions in groundwater. The main hydro-chemical types are Ca-HCO3, Ca-HCO3·SO4 because of the affects of hydro-geological conditions and human activities. Ions in groundwater mainly comes from rock weathering, Ca2+, HCO3-, Mg2+ mainly comes from carbonate weathering, Na+, SO42-mainly from the dissolution of evaporative rocks, NO3- and Cl- mainly from human activities, K+ mainly come from the weathering input of silicate rocks, The impact of human activities is mainly industrial and mining activities，and at the same time, Ca2+ and Na+ also affected by cation alternating adsorption. The contributions of carbonated rock, evaporative rock, silicate rock, human activity and atmospheric precipitation are 29.6%, 19.9%, 12.1%, 19% and 19.4%.