A polypeptide based block copolymer having biodegradability due to peptidase, a process for the preparation thereof, and polymer micelles using the same are provided. The block copolymer is a block copolymer of a polyethylene glycol-based compound having properties such that the solubility for water is different depending on the pH, but cannot form micelles due to a self-assembly phenomenon and a polyglutamic acid-based compound formed using an aminolysis reaction of glutamic acid and tertiary amine in which the end of one alkyl group is substituted with NH2, or using an aminolysis reaction of glutamic acid and triamine.
