By means of the hierarchical analysis method, taking Maduo County (a typical area of the QinghaiTibet Plateau) as an example, the structure and functions of the plateau ecological environment, the dynamic changes and interactive mechanisms of the geographic landscapes, and the heterogeneity, abundance, and fragmentation of the landscape structure are explored. An assessing index system and an assessing method of ecological environment quality for the QinghaiTibet Plateau are established, and an assessment is conducted on the ecological environment in Maduo County. The results show that the ecological environment quality of Maduo County is at a worse level in 2004, which reflects basically the ecological environment situation in Maduo County. The ecological pattern optimization (0.4228) and prosperous variation (0.4180) are at a normal level; the function intensity (0.2764, the smallest among four assessing indexes) is at a worse level, but anthropogenic stress (0.7037, the greatest) is in a good condition, which shows that the ecological environment is hardly disturbed by human being. The deterioration of the ecological environment this region is attributed mainly to its natural environment conditions.