In order to solve the problem of incompatibility in the real world, it must be based on dialectical thinking to develop a unique and creative means and methods compatible with incompatible ones. Therefore, in this paper, by means of mathematical tools and extension set matter-element transformation analysis method, the extension set are discussed deeply the practical background and its relationship with the classic set, fuzzy set, on the basis of further discussed from the philosophical foundation and mathematical system extension set is not empty, extension domain can be changed by mapping, transformation incompatible problems for incompatible logical foundation and theoretical basis, and then seek the law to solve the problem of incompatibility and extension decision analysis method, to achieve the modernization of the enterprise and the best economic benefits for enterprises to provide the best scientific decision.