The invention provides a method for producing high-purity anhydrous magnesium chloride by using bischofite. The method comprises the following steps: preparing an aqueous solution from the bischofite, and carrying out centrifugal spray drying to prepare magnesium chloride dihydrate powder; mixing and calcining the magnesium chloride dihydrate powder and ammonia chloride, and respectively collecting a anhydrous magnesium chloride coarse product and an ammonia chloride product; mixing and distilling the anhydrous magnesium chloride coarse product and sulfoxide chloride, and respectively collecting sulfoxide chloride and high-purity anhydrous magnesium chloride solids. In the whole technological process, no exogenous impurities are introduced, and the production cost is low; the purity of the prepared anhydrous magnesium chloride is up to 99.98 percent or above, the moisture content is 0.003 percent or below, and the content of magnesium oxide which is a harmful impurity is 0.02 percent or below, so that the prepared anhydrous magnesium chloride completely meets the raw material standard of electrolytic metal magnesium. Furthermore, the method passes through the pilot test, and is relatively low in requirements for corrosion property and sealing property of technological equipment, easy to operate and suitable for industrial large-scale production.