This paper aims to study the feasibility of two solid waste which are steelmaking slag and fly ash as desulfurization and denitration absorbents by microwave. Under the optimal operating conditions, the removal efficiencies of 70.9% and 69.6% are achieved for SO2 and NOX respectively. The microstructure of before and after the adsorbent reaction are analyzed by SEM. Base on the experiment research, he mechanisms of simultaneous desulfurization and denitration are investigated in this paper. The research provides a new approach to resource recycling of steelmaking slag and fly ash. And the result has great significance to recycle solid waste and preserve the sustainable development of industrial economy and environment.