The cultivated land production factor originally developed by Wackernagel was revised based on the data from the year of 2009． Using the principles and models of ecological footprints，this study proposed a ecological pressure index model and prediction models to calculate the ecological footprint，ecological carrying capacity，and ecological surplus/loss of Xi'an City from 1997 to 2009． The results indicate that from 1997 to 2009，the ecological footprint increased 0．509 7 hm² per person，the ecological carrying capacity 0．152 0 hm² per person，and the ecological pressure index had changed from 1． 45 to 3． 88，indicating Xi'an City had been overloaded heavily and increasingly． In brief，the environment of Xi'an City is ecologically unsafe and its sustainable development could be at risk．