Abstract:The average molecular weight and molecular weight distribution is the important index that decided the quality of polymerization product. Polymerization degree distribution function directly describes molecular weight distribution of polymerization products, therefore, it is theoretically and practically important to research the degree of polymerization distribution. Based on polymerization mechanism as the main line, first, the general formula of instantaneous polymerization degree distribution function fn(j) based on the quantity was deduced, and then the cumulative polymerization degree distribution function Fn(j) based on the quantity was worked out according to the relationship of Fn(j) and fn(j). The instantaneous polymerization degree distribution function fw(j) based on the weight was solved in accordance with the relationship of fw(j) and fn(j), further, the cumulative polymerization degree distribution function Fw(j) based on the weight was solved on the basis of the relationship of Fw(j) and fw(j). Finally, the polymerization degree distribution function of different polymerization reaction was inferred according to reaction mechanism.