Activated carbon has an extremely important application in the field of industrial flue gas purification due to its unique pore structure and surface properties. However, the small pore volume, wide distribution of micropores and small specific surface area of ordinary activated carbon made its adsorptive property cannot meet the needs of deep purification. The modification of activated carbon optimize its pore volume and aperture, improve its porosity and surface acidity and alkalinity, and therefore improve the adsorption performance of activated carbon. In this paper, the research progress of modified activated carbon under acidic, alkaline and neutral conditions over recent years has been summarized. And based on the existing shortcomings and bottlenecks of activated carbon modification. The research focus on activated carbon modification in the future is suggested.