The invention relates to the field of wastewater treatment and discloses a method for treating desulfurization wastewater. The method comprises the steps of carrying out MVR evaporative crystallization treatment on the desulfurization wastewater, and carrying out flue evaporation treatment on remaining mother liquor of the MVR evaporative crystallization treatment, wherein the volume of the remaining mother liquor of the MVR evaporative crystallization treatment is 5% to 10% that of influent. By adopting the method disclosed by the invention, the condition that a byproduct, i.e., flue dust is further applied to the field of building materials cannot be affected, meanwhile, high-grade sodium chloride industrial salt is obtained, and finally, the zero discharge of the desulfurization wastewater is achieved.