Typical branching copolymerization is discussed. From the connotation regularity of relevant functions of variables, a curve model of Tchebycheff meaning is simulated in Euclidean space and then homopolymerization is approached in copolymerization so that the variation regularity of branching monomer concentration can be obtained. By this method, the most realistic description of monomer variation is obtained from data processing of regression and simulation. On the basis of this work, branching initiation is handled. Then vector analysis is introduced into chain propagation in linear space of n dimensions, Laplace transform is utilized for recurring, and the dynamic formula of branching chain propagation, including chain transfer, is inferred. As a result, a series of microscopic information of branching kinetics can be obtained.