Land use change is a self-organized behavior of conversion from low niche level to high level,including two aspects of its structure and intensity.Only under the control and con-cordance with land-use niche in different levels,the balance of its resource field can be kept in certain arable land maintenance.And this balance is the precondition to keep the dynamic bal-ance maintenance of total arable land.On the basis of the niche theory and the system boundary theory,in this paper we made up the model of land-use niche and took the Xishan City,Jiangsu Province as an example to quantitatively analyze interactive intensities in different land use types.The study shows that the cropland loses easily because the niche difference between non-a-gricultural land and agricultural land is big and the urbanization process gets fast.At last we dis-cussed an approach to set up mechanisms of cropland conservation using the resource flow field theory.At present level,it is more significant that land use niche is as a new method in LUCC studies.