Abstract: In order to guide the management of central urban food security,the paper put forward divided early warning methodology. A central urban food security divided early warning indicator system was built,the alarm rankers and thresholds were determined,and the divided early warning model was introduced. Taking City A as an example,application of the model shows that：the overall food security situation is better in 2010,but there are still minor problems because of the food processing industry slowdown in 2009. Empirical results indicate：though the model is practical,it needs further improvement and development.