Preparation method of high-purity D-glucosamine sulfate

The invention relates to a preparation method of high-purity D-glucosamine sulfate, which is characterized by comprising the steps of: dissolving: weighting an alkali material into an organic solvent to prepare an alkali solution; freeing: adding the D-glucosamine sulfate with purity not less than 95 percent into the alkali solution under stirring, reacting to prepare a mixed solution containing chloride crystals and free D-glucosamine; desalting: filtering the mixed solution to remove chloride to obtain an organic solution containing the free D-glucosamine; salifying: dropping sulfuric acid into the organic solution obtaining the free D-glucosamine for reacting to prepare the D-glucosamine sulfate; and refining to obtain the finished product. The method has advanced operating process, simple equipment and less pollution; the used organic solvents can be recycled; and the prepared high-purity D-glucosamine sulfate contain no potassium, sodium or chloride ions, has no use contraindication, and is safe to use.