Abstract: Baiquan County in Heilongjiang Province is a typical black soil erosion area of northeast China. After years of ecological restoration, the local ecosystem has been improved remarkably. Remote sensing ecological indices(RSEI), composed of four indicators including the green, humidity, heat and dryness indices retrieved from remote sensing images, can reveal the ecological environment status. For timely and quick monitoring of the eco-environment in soil and water loss areas, Landsat images from 1985, 1996 and 2006 Landsat TM and 2015 Landsat OLI were used as a data source to retrieve values of these four indicators to form the RSEI by the principal component analysis method, and then RSEI was used to assess and analyse the ecological environment quality of Baiquan County from 1985 to 2015 based on RSEI. The study shows that in the past 3 decades, Baiquan's RSEI value went up 31.94% from 0.645 to 0.851. The area of improved eco-environmental quality is larger than the part that remains degraded, which indicated that the eco-environmental quality has been improved on balance. The overall eco-environmental quality index of Baiquan County rose to 4.87 from 3.78, while the composite index of each county increased to different degrees. In terms of the spatial distribution, the amplitude of the indices of southwestern and southern towns were greater than those of northern towns, and indices of the central area remained steady. The quality of the ecological environment was improved significantly in the key areas of soil and water loss. Stepwise regression analysis showed that the chosen indices are key ones for eco-environmental quality. The green degree has become an important indicator of the positive effects of ecological environment quality in the study area, which suggested that ecological management measures such as the project of Afforestation and Convert Cultivated Land into Forest playing an important role in improving environmental quality. The research showed that RSEI can comprehensively characterize the eco-environmental quality of soil erosion areas, illustrating the fact that the overall quality of the eco-environment improved continuously in Baiquan County, and that remarkable results have been achieved from water and soil erosion control.