The invention discloses a process for treating flue gas through advanced oxidation of plasmas. In the process, sulfur-containing and nitrate-containing flue gas, a cooling system, a low-temperature plasma module 1, a low-temperature plasma module 2, a plasma mixer, air, an ammonia mixer, ammonia water, a wet-type electrostatic precipitator and clean gas are involved. The process is used for treating the sulfur-containing and nitrate-containing flue gas; through an oxidation reaction provided by the low-temperature plasma modules and in combination with a reduction reaction of the ammonia water, an optimal process object of desulfurization, denitration and demercuration at the same time through a single flow path can be achieved, and the effects that the desulfurization efficiency is higher than or equal to 95%, the denitration efficiency is higher than or equal to 85% and the demercuration efficiency is higher than or equal to 85% are achieved; meanwhile, the process has the advantages of low using cost and low maintenance cost.