Abstract: Map overlaying method in GIS technology and equal weight summation method of factors were used to analyze the factors including soil quality, slope gradient, slope aspect, elevation, vegetation coverage and water body for assessing the ecological quality in Tangjiashan landslide-dammed lake region in 2015. The results show that: (1) in the area where the slope is larger than 30°, the soil and water loss is relatively serious, vegetation relatively is scarce, the interference is serious and the ecological quality is poor; in the area where the slope is between 10° and 30°,with the increase of slope, the soil and water loss gradually increase, vegetation coverage reduces, the interference is moderate, and the ecological quality is in medium level; in the area where the slope is less than 10°, the soil and water loss is less, vegetation is dense, interference is light and ecological quality is good. (2) in the east, north, northeast and northwest areas, the soil and water loss is less, vegetation is distributed sparsely, interference is light and the ecological quality is good; in south, west, southeast and southwest areas, the soil and water loss is more, vegetation is less, interference is serious and the ecological quality is poor. (3) in the area of elevation below 800m, the soil and water loss is the most serious with the largest patch distribution, the interference is serious and the ecological quality is poor; in the area where elevation is 800m-1600m, the soil and water loss intensifies and patch distribution is in medium level, interference is light and the ecological quality is moderate; in the area above 1600m, the soil and water loss is less with less patch distribution and light inference and the ecological quality is good. (4) the farther the area is from the water body, the better the ecological quality is; the closer the area is from the water body, the more serious the interference is; in area within 100 m from the water, the interference is the most serious and the ecological quality is the worst.