Abstract: Fully based on the research achievement at home and aboard,the author choose the method named "The Analytical Hierarchy Process" ,constructing a new type of food security early warning system，and then give the evaluation of the food security situation in The Pearl River Delta Region .The result shows that the food security in this area is in a downward trend in recent years,the overall situation belongs to“slight warning”rank.Especially there is a low-water mark in 2003.Because of the shrinkage of grain output and per capita share of grain, this area will face a certain degree of risk.In view of the evaluation according with the actual fact,we can judge that this new system is rational,acute and easy to operate.