Double-solvent extraction system P507 and N235 was used to make the non-saponification extraction process based on the ability of P507 to extract RE and N235 to extract acid. Under the condition of 5 minute oscillation, phase ratio in 1: 1 and the solution acidity 2 to 3, the extracting ability of double-solvent system was increased with the increasing of atomic number and RE concentration in solution. Under the best condition of 8 minute oscillation, phase ratio in 1: 1 and RE concentration at 1.0 mol/L, this paper has measured the average seperating factors between each RE element. The result can offer theory for P507-N235 system to apply to actual production. © 2015, Editorial Office of Chinese Rare Earths". All right reserved."