Changes of land use have great impacts on terrestrial ecosystems.The trends of land use changes were analyzed based on the land

social

economic

and environmental data.Using the methods of the composite index and analytic hierarchy process(AHP)

we established the ecological risk assessment systems considering natural

societal

and economic pressure

and evaluated ecological risk index and composite risks of land use structure including cultivated lands

forestlands

grazinglands

and water body.The results showed that the ecological risks were the greatest in cultivated lands

and smallest in water bodies.T he order of the risks is:cultivated land>woodland>land for inhabitation

mining and manufacturing > grazing and pasture land>unutilized land>land for transport facilities>land for water conservancy facilities.The ecological risks caused by economic pressure

nature pressure

and society pressure were greatest

intermediate

and smallest

respectively

while composite risk increased.The ecological risks are related to an unreasonable structure of land-use

increase in population

decrease in water resources and increase of natural disaster.