The hydrolysis and the substitution reaction of the main chain of the polymer having beta-alkoxyenoate moieties in the main chain are described. The hydrolysis of the polymer prepared from 2,2-dimetylpropylene-1,3-bis( propiolate) and p-xylene glycol under acidic conditions proceeded smoothly to obtain diols in quantitative yield by the cleavage of both ester and vinyl ether moieties. On the other hand, carboxylic acids were obtained by the hydrolysis of the polymer under alkaline conditions. The aminolysis with pyrrolidine gave the beta-aminoenoate by the selective fission of vinyl ether moieties in quantitative yield. Furthermore, a polymer having beta-aminoenoate moieties in the main chain was obtained by the reaction with piperazine via the displacement of the main chain.