Abstract: After explaining relationships between land carrying capacity and sustainable development, this paper took land carrying capacity as an index to evaluate the security of land resources. The logistic model of [SX(]DN[]dt[SX)]=r·N·[JB(（][SX(]\{K-N\}[]K[SX)][JB)）]can describe the increase of population. From the model and using the theory of entropy, this paper derived the final solution of [SX(]K[]2[SX)]≤N<[JB（(]1+[SX(]1[][KF(]3[KF)][SX)][JB))]·[SX(]K[]2[SX)], which can be taken as the population security interval for regional land resources. Taking Jiangsu Province as a case study, and after evaluating the land carrying capacity, this paper advanced the assessment standards of land resource security at three levels of living standards, namely simply having enough food and clothing, leading to a relatively comfortable life, and being welloff. The result indicated that the current land resources in Jiangsu Province at all the three levels are in safe situation, however, the population at the level of being welloff has reached the up limit of the security. Therefore, the control of population and protection of land resources are necessary. Lastly, the paper raised problems needing attention in the further research of land resource security.

Key words: land resources, security evaluation, land carrying capacity, Jiangsu Province