AbstractA kinetic model with non‐constant propagation and termination rate constants is given for a sort of anionic polymerization. The expression of molecular weight distribution and other molecular parameters are derived by a non‐steady state procedure. The effect of the reaction conditions on the molecular parameters are illustrated by numerical examples. The theoretical curves of molecular weight distribution with two or three peaks are similar to those of polymers generated in the anionic polymerization of polar monomers in nonpolar solve