Through interpreting TM image in 1989 and ETM+ image in 2005, the land use/cover database of the source region of the Yellow river had been established, and then the land use/cover dynamic information was derived by overlaying the database of land use/cover. Based on the land use/cover database, an eco-environment quality index model was used to establish the quantitative relation between land use/cover type and its eco-environment effect. The results show as follows: ①The change of land use/cover was slow and moderate, and two contrary changing trends of degradation and improvement in eco-environment coexisted. In the large region scale, the eco-environment quality kept relatively stable in the period of 1989-2005, but changed significantly in the small scale. ②Vegetation was the major factor that affected the eco-environment quality in the source region of the Yellow River, followed by grassland factor. ③The eco-environment quality index model can not only be used to study the eco-environment quality in the region scale, but also to find the main driving force of affecting the eco-environment quality.