The invention relates to a preparation method of an antioxidation nitraria tangutorum bobr extractive, comprising the following steps of: choosing, cleaning, juicing, grinding through a colloid grinder and homogenizing through a high-pressure homogenizer by taking fruits of nitraria tangutorum bobr as raw materials; then removing impurities by using a microfiltration membrane; washing with nonpolar macroporous absorption resin; and concentrating and drying so as to obtain the antioxidation nitraria tangutorum bobr extractive. The invention not only effectively reduces the production cost, shortens the extraction and separation time and reduces the energy consumption in the process course, but also enhances the yield of the antioxidation nitraria tangutorum bobr extractive through the combination action of a high-pressure homogenization technology, a membrane separation technology and a macroporous resin separation technology.