Abstract: The theory of ecological footprint was introduced and the development of Xi'an City from 1990 to 2001 assessed using the method of ecological footprint.Results show that per capita average ecological footprint for Xi'an City is 0.9012hm²/cap.in 1990 and 1.2691 hm²/cap.in 2001.Per capita average ecological footprint deficit is 0.5376hm²/cap.in 1990 and 1.2691 hm²/cap. in 2001.Analyses of the ecological footprint of Xi'an City indicate gradual increase in natural ecosystem requirements which threatens sustainable development of Xi'an City under given the ecological capacity of the city.Finally,some measures of reducing the ecological footprint deficit of the city are advanced.