Abstract: Based on the original remote sensing ecological index（RSEI）,the Google Earth Engine（GEE）cloud platform was used,selecting the enhanced vegetation index（EVI）to replace the NDVI in the original greenness index to construct and calculate the RSEI of the vegetation growing season in Changbai Mountains region from 2001 to 2020.Regression analysis,fluctuation analysis,Hurst index and other methods were used to analyze the spatial and temporal variation characteristics of RSEI in Changbai Mountains region and its climatic influencing factors were explored.The results showed that:（1）From 2001 to 2020,the RSEI in Changbai Mountains region increased slowly with fluctuation,and the overall ecological environment quality showed an increasing trend.The average values of spatial distribution of RSEI for many years had obvious differentiations.The quality of the ecological environment in Changbai Mountain Protection Region and Development Zone were relatively good,and most of Tonghua and Baishan cities were poor;（2） In the past 20 years,the stability of RSEI in Changbai Mountains region was relatively poor,and the quality of ecological environment was relatively fragile.In future,the trend of ecological environment would be generally positive,but there would be still a continuous deterioration trend in some areas;（3）The RSEI in Changbai Mountains region was mainly affected by precipitation,showing a significant positive correlation with precipitation,but not strong with temperature.