The development of brine on the coast of Laizhou Bay began at 1950s, where the present salinity of brine is 3~6 times that of the seawater. To identify the origin of salinity, stable isotopic and hydrochemical analyses have been performed on 9 samples collected in this study. The depth of sampling well fall in the range 30~80 m. According to the isotope salt effect, the values of δD and δ18O were corrected to the activity values. δD—δ18O diagram indicates that the water molecule of brine samples are originated from meteoric water rather than seawater. δ18O—Cl- and Br-—Cl- diagrams show that the salinity feature of brine was different from that of the residual evaporated marine water. Base on the chemical divide concept, the evolution of Ca2+/SO2-4 and Ca2+/Mg2+ ratios of brine suggests that the origin of the dissolved salts is not evaporated marine brine. Reactive tracers plots identify that the brine salinity was attributed to the repetitious dissolution of evaporite derived from marine salts. This paper suggests the brine is related to marine salt rather than marine water.