Building a macro and micro model of a multistage process is considered using the decomposition method, dividing the general technological system into interconnected control loops. A procedure for constructing an integrated macro model of a multistage process using a system of material balance equations for each control loop, a two-level mathematical model of a complex multistage system, developing principles for modeling and systematizing element models, the degree of aggregation, in general, controlling the technological properties of a material resource, calculating the schemes is reduced to solving a system of algebraic equations, modern technological scheme processing of a material resource, the procedure for constructing an integrated macro model multistage process (SME). A modern technological scheme for processing material resources cannot be carried out without returning circulating products when the product from subsequent nodes is sent for revision to the head of the technological scheme. The procedure for constructing an integrated macro model of SME s at two stages is considered. The task is to find the optimal solutions to the original mathematical model by interconnecting conditionally - optimal solutions of individual models. A comparison of various formal decomposition methods is performed according to previously determined criteria, and on this basis, the most preferable is chosen. When modeling multidimensional systems, one has to operate with various factors that have different units of measurement. Therefore, it is advisable to determine the dimensionless mathematical model since it is easily analyzed. The use of the latest mathematical modeling tools and modern methods of the flexible equation mainly determines the prospects of such studies.