Dynamic monitoring of ecological quality is of great significance for achieving regional sustainable management and development. Based on Landsat 5/TM images and Landsat 8/OLI images， a remote sensing ecological index was constructed using the Google Earth Engine platform to achieve a dynamic evaluation of ecological quality in the Daxing'anling Mountains region from 1986 to 2020. （1） Greenness and humidity have a positive impact on ecological quality， while dryness and heat have a negative impact on ecological quality. Heat and greenness have the greatest impact on ecological quality； （2） From 1986 to 2020， the distribution of ecological Mass distribution in the Daxing'anling Mountains changed greatly. Compared with 1986， the phenomenon of low or high ecological quality in large areas decreased， and the distribution was more uniform， and the ecological quality was more stable； （3） From the relevant statistics of the changing areas， it can be seen that the ecological quality change areas in the Daxing'anling Mountains region account for about 96.4% of the total area， with significant changes in ecological quality； （4） The ecological quality of the severely burned areas in the Daxing'anling Mountains shows a trend of first decreasing and then increasing， but the overall ecological quality of the Daxing'anling Mountains region fluctuates greatly. On the whole， the distribution of ecological quality is more stable， there is no phenomenon of local too low or too high， and the level of ecological quality is gradually improved.