The SR28 and SR29 geothermal paired wells are located in Dongli District of Tianjin, lying on the western fringe of bigsmall Dongzhuang doming in Cangxian uplift, near the Cangdong fault and at the center of the Shanlingzi geothermal anomaly area. The SR28 and SR29 geothermal paired wells use the geothermal reservoir of Wumishan Formation of Mesoproterozoic Jixian System as the target layer of exploitation and recharge. This paper analyzed the hydrogeochemical characteristics of geothermal water according to chemical analysis, and the result shows that SR28 and SR29 geothermal water belongs to continental sedimentary water formed in the strata with dissolved salt brine, that carbonate strata of Wumishan Formation constitute the storage layer of geothermal water, and that the geothermal water is likely to come from the supplement of outside sources which go through upper limestone strata. Being unpolluted and microcorrosion type water, SR28 and SR29 geothermal water does not form CaCO3 or CaSO4·2H2O scales, but sometimes may generate SiO2 scales.