Abstract: Based on the TM images and 3S technology, and by using normalized burn ratio (NBR), this paper quantitatively evaluated the fire severity of burnt area in Huzhong forest region of the Great Xing’an Mountains from 1986 to 2010, and analyzed the relationships of the fire severity with environmental factors such as vegetation type, elevation, slope, and aspect. In Huzhong forest region, the fire occurrence frequency and total burnt area had an obvious interannual change. High incidence of forest fire was from June to August, and heavily burnt area occupied 842% of the total burnt area. In the burnt area, larch forest accounted for 89.9%. 68.8% of burnt area located at the elevations from 1000 m to 1500 m, and 62.5% located in eastern, southern, western, and northern slopes. There was no obvious difference in the burnt area between sunny and shady slopes. The burnt area at the slope degrees 15°-25° occupied 38.4% of the total. High severity burnt area was the largest (70% of the total), followed by moderate severity burnt area (about 10%), and low severity burnt area and un-burnt area
(<5%). The majority of the forest fires in Huzhong forest region were of high severity fire, which caused great damages to the forest resources. It was suggested that in the forest fire management in Great Xing’an Mountains forest region, it would be urgent to implement forest fuel treatments to reduce fire severity to guarantee the forest ecosystem security.