To explore the feasibility of extracting lithium metal from brine sources, three salt solutions, FeCl(3), ZnCl(2), and CrCl(3), were selected as coextracting agents, and the extraction equilibrium of lithium was studied with tributyl phosphate (TBP) in kerosene, TBP in methyl isobutyl ketone (MIBK), and TBP in 2-octanol. The results showed that the extraction capacity followed the sequence: TBP/MIBK > TBP/kerosene > TBP/2-octanol, with recoveries from the TBP/MIBK and TBP/kerosene systems being much larger than that for TBP/2-octanol with FeCl(3) solution as the coextracting agent. The third phase was found for the TBP/kerosene system with FeCl(3) solution as the coextracting agent at a low volume concentration of TBP, which did not appear for other systems at all volume concentrations. Synergistic extraction exists between TBP and MIBK, and the weak hydrogen bond association exists between -OH in 2-octanol and -P=O in TBP. The coextracting capacity for FeCl(3) as much larger than that for ZnCl(2) and CrCl(3), and that for TBP/2-octanol with CrCl(3) was a little larger than that for others.