Abstract: Desert-oasis ecological fragile zone is a ecotone with sensitive degeneration tendency which is controlled by both desert ecosystem and oasis ecosystem. It is important to prevent land desertification and help oases extend under a good hydraulic condition. The fluctuant vulnerability and interfacial fragility are the two major types of unstable form. The causes of oasis, landscape types, fragile degree and fragile characters are chosen as the criteria for classification of the desert-oasis ecological fragile zone. With variant states, the natural environment, process of production and environment management sre found to be as a qualitative index system of assessing desert -oasis ecological fragile zone. After analyzing its characters, in this paper, according to oases'classificatory system, three general types are generalized, such as alluvial plain (or rive terrace) fragile zone, alluvial fan fragile zone and lacustrine plain (or delta) fragile zone. The classification and assessment systems are systematic, complete, objective and flexible to assess desert-oasis ecological fragile zone. It is tested to assess alluvial plain fragile zone along the Tarim River. Fragility and artificial disturbance cause many environment problems, especially land desertification. Some suggestions are put forward for dealing with these problems in this paper.

Key words: oasis, ecological fragile zone, desertification