Abstract: According to the formation,transition,consumption,storage and drainage of water resources as well as the landforms and vegetation,the ecosystem in the continental river watershed of arid area can be divided into five main types,i.e.the mountain,water,artificial oasis,natural oasis,and desert ecosystems.All the ecosystem types rely on the deserts as their backgrounds,the mountains as their foundations,the waters as their dominants,the artificial oases as their cores,and the natural oases as their protective screens.The improvement measures of the ecosystem in the watersheds are to improve the environment in the mountains for conserving water,to rationally utilize the water resources for maintaining a stable ecosystem,to construct the artificial oases for optimizing the living bases,and to protect the natural oases for making the ecological benefits,for controlling the desertification,and for reducing the natural hazards.

Key words: arid area, ecosystem type,improvement measure