Ecological footprint is an important indicator to evaluate the sustainable use of ecosystem.Based on the theory of ecological footprint,the ecological footprint and ecological capacity of the Yangtze River Delta during the period from 1996 to 2004 are calculated and analyzed using the method of variable world average yield.Results show that the ecological deficits continue to increase,which demonstrates that great human-environment conflicts exist.The Yangtze River Delta is in a state of unsustainable development.