Flue gas desulfurization of coal-fired boilers is an important measure to control air pollution emissions and effectively prevent acid rain. At present, there are more than 200 flue gas desulfurization technologies researched and developed at home and abroad. Among them, wet flue gas desulfurization technology is widely used in coal-fired boilers due to mature technology and high efficiency. This paper analyzes two commonly used methods, gypsum desulfurization (to waste The technical process of desulfurization (for waste) with ammonia method, and the existing problems are analyzed and discussed.