This paper summarizes the relationships between hydrochemical proxies of Mg²⁺, Ca²⁺, Mg/Ca and the salinity from more than four hundred lakes in the Qinghai-Tibetan Plateau. We discuss its variation characteristics by different samples from varied place and time, as well as natural evaporation. Mg²⁺ shows a stable positive relationship with salinity in Lakes in the Qinghai-Tibetan Plateau, while Ca²⁺, Ca show poor and unstable relationships with salinity. For carbonate water types in the lakes, however, no significant relationship is observed between Mg²⁺, Ca²⁺ and Mg/Ca and salinity in carbonate typed lakes. Mg²⁺ shows positive relationship with salinity in sulphate typed lakes, and Ca²⁺, Mg/Ca remains poor relationship with salinity. While in chloride typed lakes, Mg²⁺, shows distinct positive relationship with salinity, and Ca²⁺ also shows positive relationship to some extent with salinity. Ca still shows no clear relationship with salinity. In individual lakes, Ca²⁺ and Mg/Ca still show unstable and/or poor relationship with salinity, while Mg²⁺ keeps remarkable positive relationship with salinity. It is concluded that Mg²⁺ is a useful indicator for paleosalinity reconstruction in the Qinghai-Tibetan Plateau.