Abstract: Based on the theory of organizational ecology, the theoretical analysis model of the evolution mechanism of the united cooperatives was constructed. It is found that the characteristics of the co-builders shape the ecosphere effect and niche effect of the co-builders. At the beginning of the establishment of united cooperatives, the effect of the builder determines the selection of its initial niche and the shape of the ecological circle, and forms the effect mark of the builder of united cooperatives. The causal feedback mechanism of ecological circle width, balance, complementarity of resources and the matching degree between the ecological circle and the ecological niche of theassociationconstitute the path of element connection in the ecological circle. If the utility of the builder can be transformed into the ecological coupling effect through the path of element connection, united cooperatives will grow normatively; if the differentiation of element connection leads to the distortion of coupling effect, united cooperatives will drift qualitatively and alienate into the enterprise; if element connection fails, the internal and external coupling of unitedcooperatives will fail, and united cooperatives will become shell cooperatives.