The Mami Co Saline Lake, located in Gertse County, Ali Prefecture, Tibet, has lithium chloride reserves of 25 million tons and solid boron ore reserves of 3686 million tons. It is one of the large lithium boron deposits in Tibet. The river water, spring water and lake water in the Mami Co basin were collected, and their total dissolved solids (TDS), pH, major chemical composition were analyzed. A comparative study of mathematical statistical analysis, Piper aniontriangle map, and Gibbs diagram shows that water in the Mami Co basin has different hydrochemical types. The hydrochemical type of river runoff is Ca·Na·MgHCO3·Cl, the hydrochemical types of river tributaries are CaHCO3 and Ca·MgSO4·HCO3, hydrochemical types of spring water are Mg·CaHCO3·SO4 and Na·MgHCO3·Cl, the hydrochemical type of lake water is NaCl. The hydrochemical compositions are mainly affected by weathering of rocks and evaporation crystallization. The major ion concentration in the river water is between the snow melt water and spring water, and closer to the spring water concentration. It shows that the river water mainly depends on recharge by spring water. The oreforming materials in saline lake are derived from rock weathering and deep waterrock reaction. The water of the Mami Co Saline Lake is in positive equilibrium, and the continuous rise of water level will have a certain impact on the ecology,local livelihood, and production in the lake area. It is suggested that a dynamic monitoring of water level should be carried out.