The invention relates to the technical field of desulfurization, denitrification and dust removal, and concretely relates to a spraying first-stage absorption tower. The spraying first-stage absorption tower comprises an absorption tower shell, the internal of the absorption tower shell is divided into a top reaction cavity, a middle reaction cavity, a middle mixed flow cavity and a bottom liquidstorage cavity from top to bottom, and a supporting frame is fixedly mounted under the absorption tower shell through bolts. The spraying first-stage absorption tower has the following advantages: flue gas can be pre-dedusted through a pretreatment device, and is fully reacted in a periodic gas supply and cyclic purification manner, so that the phenomenon of easy discharging of insufficiently reacted gas by a traditional absorption tower capable of continuously supplying the gas is avoided; and gas-liquid full contact and reaction can be realized by combining various reaction processes, such as a stirring reaction using stirring paddles, an auxiliary reaction using a middle reactor and a spraying reaction using an atomization spraying head, with cyclic reaction, so that the reaction absorption efficiency is effectively improved, and the flue gas purification efficiency is improved.