Abstract: Underground brine，salt lake brine and ore are rich in lithium resources. Lithium extraction is mainly carried out from the former two，so it needs to be rationally developed and utilized.The variation law of lithium ion concentration in the process of evaporation and concentration of underground brine in Jiangling，Hubei Province was studied.Firstly，the salt?鄄dis?鄄charging law and the variation law of lithium ion concentration in the process of Jiangling underground brine concentration were studied separately.Constant chemical composition analysis and lithium ion concentration determination of Jiangling underground brine by evaporation and concentration were carried out.The experimental results showed that the concentration of sodium chloride increased first and then decreased with the increase of evaporation rate，and the concentration of potassium chloride increased with the increase of evaporation rate.Sodium chloride began to precipitate when the evaporation rate was 34.80% and potassium chloride began to precipitate when the evaporation rate was 66.10%.The lithium ion concentration increased as the evaporation rate increased.By determining the potassium precipitation point and measuring the content of each ion in the mother liquor，the change rule of lithium ion concentration during the continuous evaporation of the mother liquor was studied，which provided basic data for extracting lithium from Jiangling underground brine in the future.

Key words: underground brine；evaporation and concentration；mother liquor；lithium；crystallization