Qinghai Lake coitchment,a typical complex ecosystem in the arid-semi arid region of Northwest China,is competed of grass lands, lakes Tdesert,farm lands,cities and towns.The system is characterized by dry and cold alpine,strong solar radiation,traffic inconveniece,a sparse population and backward econom-mic conditions,therefore showing a w-eak capacity of resistance and a lower output.Under warm and dry climatic conditions,the unreasonable human activities cause a series of eco-evironmental degradation,in-eluding land desertization,vegetation deterioration, decline of lake level,decrease in fish catch, ecological degradation in Bird Island and potential industrial pollution.