15 water samples were collected through chemical analysis in Jiangyou City emergency water source and its upper and lower reaches. The hydrochemical characteristics of the groundwater source and the change law of hydrochemical of the upstream and the downstream were analyzed according to the concentration of main ions, Piper diagram and the variation along the Jianjiang River. The results show that the groundwater in the study area is weak alkaline belonging to hard water and extremely hard water. The average value of TDS is 281.446mg/L, the main cations are Ca2+ and Mg2+, and Na+ + K+ the second; the anion is mainly HCO3- and SO42- with less Cl- and the chemical type of groundwater is HCO3--Ca2+. From upstream to downstream, there is an overall increase in both TDS and main ions of groundwater. The chemical type of groundwater changed from HCO3--Ca2+ type to HCO3-·SO42--Ca2+·Mg2+ type.