Abstract: Taking Xichuan County, Henan Province as research object, water source area of the South to North Water Transfer Middle Route Project, landsat TM/OLI remote sensing image data from Xichuan County in 2007, 2013, and 2019 were used in conjunction with the ENVI platform to evaluate ecological and environmental changes in water source area of the South to North Water Transfer Middle Route Project in recent years．By using principal component analysis, four indicators of greenness（NDVI）, humidity（WET）, dryness（NDBSI）, and heat（LST）were integrated into ecological remote sensing index（RSEI）of water source area to evaluate ecological environment quality of study area from 2007 to 2019．From 2007 to 2019, overall ecological quality of research area was mainly average and good, with both accounting for over 75% of the area．Average RSEI values for three periods were 0.7565, 0.6989, and 0.709, respectively．Ecological environment quality of water source area of the South to North Water Transfer Middle Route Project showed an overall trend of first decreasing and then increasing from 2007 to 2019, with an increase in the area of ecologically sound areas．