Abstract: Based on the stratigraphy, structure, hydrogeology and hydrogeochemical environment, the distribution and forming condition of the soda water in Baoquan Town,Kedong County of Heilongjiang Province are discussed. That soda is formed by the processes of sedimentation, volcanic activities and fault structure. The natural soda water occurs mainly in the pore-fissure confined aquifer of the clastic rock of Nenjiang group, Upper Cretaceous. Affected by the Himalayan volcanic activities and fault movements, the closed reduction environment of the Upper Cretaceous aquifer in Kedong County changed to open or semi-open oxidation environment, leading to decarbonization. The ions of HCO₃^- and Na⁺ became the main components of the groundwater. The natural soda water is thus formed.