In recent years, the concept of the ecological footprint developed by Wackernagel and Rees in the mid-1990s has gained much attention. Basically, the ecological footprint is the amount of productive land required to support the consumption of a given population definitely under existing technology. As a static model, the ecological footprint has been extensively used to assess the condition of sustainable development of various regions at specific points in time. However, little information is available on time series analyses and predictions of the ecological footprint. An ecological footprint time series of Chongqing in China was calculated from 1997 to 2004. Predictions of that from 2005 to 2009 were performed with the Gray Model method developed by Deng in the 1980s. The method can predict the development of the system using the continuously differential equation. In Chongqing, the ecological footprint was 1.2108 hm² per capita, while the actual ecological carrying capacity was 0.4696 hm² per capita in 2004, thus leading to ecological deficit of 0.7412 hm² per capita. From 1997 through 2004, the ecological deficit of Chongqing increased annually as the ecological footprint increased. The ecological carrying capacity, decreased, however, indicating an unsustainability of the present developmental and consumption state of Chongqing. The ecological deficit of Chongqing will reach 0.8695 hm² per capita in 2009. Based on these results, measures to reduce the ecological deficit for Chongqing were suggested such as controlling the population, adopting suitable technology to increase efficiency in resource use, changing manners of production and consumption, and protecting the environment.