North Qiangtang basin in Tibet is one main Jurassic marine area of potash exploration. There is a series of modern springs with a potassium anomaly in Dogai Coring area. Research on origin of salt springs has an important significance for potash exploration and scientific value. For this study forty salt springs water samples were taken from field. Chemical composition, δ34S and 87Sr/86Sr of salt springs were determined in laboratory. Analysis results indicate that salt springs water have a high concentration of Na+, Ca2+, K+, Cl-, and a poor concentration of Mg2+, SO42-, HCO3-. Content of Cl- has more than 50% TDS and positive correlation with TDS. Moreover, Na+, Ca2+, K+ have a positive correlation with TDS. According to nNa+/nCl- and Br-•103/Cl- of salt springs, springs water are from stratum lixiviation water. The δ34S value of water samples from Yuanquanhe, Dongwenquan and south bank of Dogai Coring are consistent with δ34S value of Jurassic seawater. It demonstrates that springs water might dissolve gypsum of stratum when springs water travelled under the ground. The figure of 1000/Sr-87Sr/86Sr illustrates that migration path and forming process of springs water from every sampling location are different from each other. The comparison for 87Sr/86Sr of salt springs and its background value shows that groundwater might lixiviate evaporite from 2nd Member of Xiali Formation and 1st Member of Suowa Formation. Xiali Formation and Suowa Formation are the most possible stratum of forming potash.