The invention provides a method for treating an exhaust gas containing nitrogen oxides and volatile acids. The method comprises the steps of A) oxidizing and washing the exhaust gas containing the nitrogen oxides and the volatile acids at a pH of 5-6 to obtain a first washing gas, wherein an oxidized and water-washed medicament comprises a chlorite solution and first alkali liquid; B) after the first washing gas is atomized and humidified, conducting collision and dissipating to obtain a treated first washing gas having a particle diameter greater than or equal to 0.5 micrometer; C) reducing and water-washing the treated first washing gas to obtain a second washing gas, wherein a reduced and water-washed medicament comprises a reducing agent solution and second alkali liquid; D) conductingoxidation, deodorization and washing on the second washing gas to obtain a third washing gas, wherein an oxidized, deodorized and water-washed medicament comprises a hypochlorite solution and third alkali liquid; E) filtering the third washing gas, and controlling a filtration precision to be 0.5-2 micrometers to obtain a purified treated gas. The method can remove the volatile acids and the nitrogen oxides efficiently, and have no white smoke phenomenon.