Monitoring the Natural Forest Protection Project in the upper reaches of the Yangtze River using medium-resolution imagery can objectively evaluate the effectiveness of the Natural Forest Protection Project in enhancing both the quantity and quality of forest resources. Based on Landsat TM/OLI images from 2001, 2009, and 2018, monitoring of forest resource distribution and ecological environment quality changes in Ebian Yi Autonomous County was conducted. The results indicate: (1) Forest coverage rate increased by 11.9%, while the area of barren mountains and wasteland decreased by 72.8%. The increased forested land primarily originated from the conversion of suitable barren mountains, wasteland, and cultivated land, reflecting the construction effectiveness of the Natural Forest Protection Project. (2) The remote sensing ecological index indicates an overall improvement in ecological environment quality, transitioning from good to excellent. This study can provide a decision-making basis for the formulation and revision of natural forest protection policies in the new development stage.