The paper aims at the problems of food security,the decline in land ecological quality and the social and economical security in the process of land utilization.A system of evaluation criterions was set up based on the PRS evaluation model of land use.The weigh of all the criterions was then determined using Delphi method.Finally, quadratic function was used to work out the degree of land security.The result indicates that in terms of the land security value,the status of land security in Chongqing was better in 2004 compared with that in 1999,and now is at the beginning of a security stage.