Abstract: The published data up to now concerning polyether-lithium liquid-liquid extraction systems, can be summarized by the equation, εp= (α-1) /1+0.46(1-P) ,where a denotes the isotope separation factor, P--the ratio of thelithium concentration in the organic phase to the initial concentration of crown ethers. εp,the enrichment coefficient as P=100%. Based on the changes in εp, P,α and D(distribution ratio),the functions of factors such as polyethers structure, polyether's side group, polyether's concentration, organic solvent,negative ion of lithium salt and lithium salts concentration,are discussed and reported.