Ring-opening polymerization is one of important chemical reactions in chemical industry

and also is very hard section in the polymer chemistry course due to it contains many features such as chain polymerization

stepwise polymerization

and cationic (or anionic) polymerization. The authors developed a series of pithy formula about ringopening polymerization to guide the teaching course based on the features of ring-opening polymerization reaction during the practical teaching process. Moreover

the detailed illustrations could be expressed by this manuscript. The authors hope this kind of pithy formula can provide helps to teachers and students

and decrease the teaching difficulties of ring-opening polymerization section. This manuscript can help students clearly understand the mechanisms and kinetics in ring-opening polymerization.