The solubility of moxidectin in different solvents is different.The insoluble and polar two-phase solvent is used for liquid-liquid extraction to reduce the content of A impurity and E+F impurity in moxidectin.The results showed that the best solution of 30% methanol aqueous solution and heptane dissolved in 20∼25°C environment, and the best extraction times is equal volume extraction 3 times.