Isothermal dissolution method and turbidity technology were employed to measure the solubility, the supersolubility, and the metastable zone width of Li2CO3 in mixed LiCl-NaCl-KCI-Na2SO4 solutions at temperatures ranging from 293.15 to 353.15 K. It was found that the solubility values of Li2CO3 increased as the Na2SO4 concentration increased and decreased as the NaCI and KCI concentrations increased. In addition, these two opposite effects both affected the solubility of Li2CO3 in mixed electrolyte solutions. NaCI and KC1 impurities decreased Li2CO3 super solubility, which could be overcome by adding a small amount of Na2SO4 salt. The influence of the impurities on the metastable zone width differed from their influence on the solubility. The metastable zone width in electrolyte solutions was mainly affected by Na2SO4 salt, where it increased with the increasing Na2SO4 concentration. Meanwhile, NaCl and KCl salts had little impact on the metastable zone width. Overall, this study provides the basic data for the crystallization process of the lithium carbonate from salt lake brines U in the industrial production process.