Polylactic acid segmented copolymer and preparation method thereof

The invention provides a preparation method of a polylactic acid segmented copolymer. The preparation method comprises the steps: carrying out etherification and polycondensation reactions by taking a diacid source, a diol source and multifunctional monomers as raw materials in the process of preparing the polylactic acid segmented copolymer to obtain aliphatic copolyester; then, initiating lactide to carry out ring opening polymerization by taking the aliphatic copolyester as an initiator to obtain the polylactic acid segmented copolymer with a long branch chain. The raw materials for preparing the polylactic acid segmented copolymer prepared by the invention are easy to obtain; the polylactic acid segmented copolymer is prepared through simple etherification, polycondensation and ring opening polymerization so as to be simple in preparation method; the polylactic acid segmented copolymer is structurally provided with the long branch chain.