Taking corn stalks in Beijing Daxing District as the main raw material, and the peanut shells and wheat straw as affixation, the combustion characteristics of mixed materials were studied by using thermogravimetric analysis. The combustion dynamics was analyzed by using Coats-Refern method to offer practical and theoretical data for crop straw combustion. Studies showed that combustion curve of three samples had two distinct peaks, which could be divided into four basic stages: water evaporated to dryness, the combustion of volatiles, fixed carbon combustion and burnout. At the same time, a larger overlapping area was laid in the entire combustion stage. The combustion characteristics and kinetic parameters of mixed materials were influenced by adding peanut shells, and less affected on adding wheat straws.