Preparation method of high-quality cytidine sulfate crystal

The invention discloses a preparation method of a high-quality cytidine sulfate crystal, which comprises the following steps: dissolving a cytidine crude product in water, adding a sulfuric acid solution to adjust the pH value to 1.0-2.5, and filtering to obtain a filtrate; adding the filtrate into a crystallizer, stirring, and obtaining cytidine sulfate crystal mush by adopting a cooling and solventing-out coupling crystallization mode; and carrying out suction filtration on the cytidine sulfate crystal mush, washing, taking a solid part, and drying to obtain a white crystalline cytidine sulfate solid. According to the method disclosed by the invention, the nucleation and growth processes of the cytidine sulfate crystal are influenced by regulating the pH value of the system and the synergistic effect of the solvent, and the high-quality cytidine sulfate crystal product is prepared by adopting cooling coupling specific anti-solvent crystallization. The cytidine sulfate prepared by the method has the characte