The invention relates to a method for preparing high-purity 
Moxidectin, which comprises the following steps: (1) macroporous absorption resin 
chromatography is carried out on 
Moxidectin solution which is purified in advance, the obtained product is eluted by the 
mixed solution of polar 
organic solvent and water; (2) the eluent is extracted by 
methylene dichloride, and then 
solvent is removed by conventional concentration; (3) protective reaction is carried out on the condensate to obtain upper protective liquid; (4) macroporous absorption resin 
chromatography is carried out on the upper protective liquid, and the 
chromatography is eluted by the 
mixed solution of the polar 
organic solvent and the water; (5) the eluted upper protective liquid is oxidized, and then deprotection and oximation reaction are carried out to obtain the reaction liquid of the 
Moxidectin; (6) macroporous absorption resin chromatography is carried out on the reaction liquid of the Moxidectin, and the chromatography is eluted by the 
mixed solution of the polar 
organic solvent and the water, so that the obtained eluent is the high-purity Moxidectin solution; the product can be separated out of the solution by using the conventional concentration and 
crystallization technology if necessary. As the macroporous absorption resin chromatography is used for separating instead of 
silica gel chromatography, the method is not only stable and controllable as well as is easy to industrialize, but also improves the product purity, the quality and the yield.