The research of the relation between niche construction of crop and its evolution belongs to the new field in the niche theory. Taken the crop in semi-arid region as the object,the  paper systematically analyzes the development of the niche connotation and the mechanism of the niche construction,researches the special law of the cooperated evolution between the crop species and the change of their environments,proposes the evolutionary inertia measured by the fitness of the crop niche and the evolutionary momentum measured by the deviation between the real niche and the center point,and constructs the corresponding mathematical model and analyzes the real experiment data.The main results are:
    (1) Niche construction describes the crop species with evolution scale,materially.Crops determine its niche through metabolism,action and selection,including some creation and destruction of its niche.Based on the Hutchinson’s niche theory ,the paper build up the pattern of n-dimensional hypervolume niche construction.
(2) On the change of evolutionary inertia and momentum with the effect of niche construction,the calculation and analysis show that the pressures of the natural selection and the artificial selection have different directions,and the niche construction can lead to different law of evolutionary inertia and weaker evolutionary mementum.Due to the double  effects of natural and artificial selection,the rule of crop is special compared with the natural one in the natural one in the niche construction.
(3) On the relation between the crop evolution and the changeable resources in its enviroments,the evolutionary inertia increases and the evolutionary momentum decrease with the increasing of the soil nutrients.It is the evolutionary effect on niche construction by soil nutrients.The above results can be the theoretical supports to the breed and selection of the crop species and the artificial regulation of the crop fields.