With the theory of sustainable development as guide for the agriculture of China, farmland in Houhu region of the Jianghan Plain was selected for case-study on introduction of the niche 2 fitness theory into multi-suitability evaluation of cultivated land. Quantitative analyses of niche fitness of and restrictive factors for rice, wheat, cotton and rape, were carried out by means of weighted average and limiting factor models. The results indicate that the niche-fitness value in this area is in medium on the high side with the peak value reaching 0.958, suggesting the region meets the basic requirements of the crops; and farm-lands in Grade 1 and 2 account for 75%; rice ranks first in terms of acreage of niche-fitness, amounting to 65.54%, and wheat comes the next. CEC, soluble phosphorus and accessibility to roads are the primary niche factors that restrict land productive potential in this area. These results of the study can find direct application to supervision of agricultural production, to reasonable utilization and scientific management of cultivated land resources.