The basin fluid is the very active factor in the sedimentary basins, the hydrogeochemistry is mainly controlled by fluid- rock interaction. The source and genesis of the formation water are very complex. It is necessary to combine the water isotopic components, major ions, trace elements and radionuclides to explain the genesis and source of the formation water. This study described applying interrelationship of geochemistry characters to research the formation water, in order to trace fluid flow direction, discriminate the sedimentary environment, carry out the regional stratigraphic correlation, and use the hydrodynamic effect to find the favorable area for drilling.