and b shows the effect of simultaneous desulfurization and denitrification by microwave reactor with different microwave power using potassium permanganate (KMnO4) as oxidizing agent and zeolite as catalyst. The “PP–MW”, “Z–MW” and “PPZ–MW” profile are represented by potassium permanganate, zeolite, potassium permanganate and zeolite under the microwave respectively. The conversion of desulfurization purifying efficiency increases from 33.3% with 119 W microwave power to 95% with 280 W, and the conversion of denitrification increases from 85.6% with 119 W to 98.2% with 280 W, showing excellent desulfurization and denitrification effect of the microwave power with the potassium permanganate and zeolite. The reason for over 259 W microwave power the shape of the “PPZ-MW” increases could be that high temperature keeps the catalytic surface reaction of microwave desulfurization and leads to the enhancement of SO2 removal efficiency up 0.7%. The experimental results showed that the optimum microwave power on desulfurization and denitrification is supposed to be 259 W.