In this paper, after analysing the current land productivity and estimating the potential crop productivity, an evalution model of land resource productivity-Model of Fuzzy ISODATA Claster Analysis (MFICA) and an optimization model of land resource utilization-Model of Linear Programming (MLP) are set up in the IBM-PC computer. Then, on the basis of above, the regional agricultural productivity and the land resource carrying capacity in Dingxi county for the years 1990, 2000, 2025 and after 2025 are given. At last, the development of land resource carrying capacity and the future trend of land-food-population relationship in Dingxi county are explained.It provides a workable way for the study of regional land resource carrying capacity.