[Objective] To In order to better monitor and evaluate the ecological quality of hilly areas, it is necessary to construct a accurate remote sensing ecological index of middle and high vegetation areas, and explore the influencing factors of its ecological quality, so as to provide scientific support for the balance between development and ecology in Taojiang County. [Method] To address the saturation issue of the Normalized Difference Vegetation Index (NDVI) in densely vegetated areas, this study introduces the kernel Normalized Difference Vegetation Index (kNDVI) and integrates it with humidity, dryness, and heat factors to formulate a Modified Remote Sensing Ecology Index (MRSEI). Utilizing this index, the ecological environment quality and its temporal variation in Taojiang County from 2000 to 2021 were quantified. Additionally, a parameter optimized geographic detector model was employed to analyze the driving forces of six influencing factors, including vegetation coverage, precipitation, temperature, land use, altitude, and population density. [Result] (1) Compared with the RSEI model, the MRSEI model can effectively address the issue of NDVI saturation in areas with high vegetation cover, enabling a more precise monitoring of the ecological environment in Taojiang County; (2) The average RSEI values for the five periods from 2000 to 2021 in the study area were 0.77, 0.84, 0.83, 0.75 and 0.79, respectively, indicating a satisfactory performance in ecological environment quality with a trend of improvement-deterioration-improvement; (3) From the analysis of the factors influencing ecological environment quality, land use emerges as a key factor determinant in the study area. In the factor interactive detection analysis, the interaction between land use and elevation were strongest. [Conclusion] In summary, variation of the ecological environment quality in Taojiang County is primarily influenced by a combination of natural and anthropogenic factors. The research results can provide technical reference for carrying out effective ecological environment protection and restoration measures in Taojiang County.