The utility model provides a spray gun and desulfurization process system for desulfurization process system, the spray gun includes desulfurizer pipeline, desulfurizer pipeline both ends are providedwith desulfurizer entry and desulfurizer export, wherein, the spray gun includes still that steam spouts the entry, steam spout the entry be used for to the desulfurizer pipeline spout into steam tothe atomizing of messenger's desulfurizer. According to the utility model discloses a spray gun can make desulfurizer and flue gas intensive mixing, and improve and adsorb and reaction efficiency fordesulfurization process to improve desulfurizer desulfurization efficiency, realize that the SO2 content after the desulfurization is less than 50mgNm3, be superior to national standard emission requirement far away.