Aliphatic-polylactic acid segmented copolymer

The invention provides an aliphatic-polylactic acid segmented copolymer. The preparation method of the copolymer comprises the following steps: polymerizing aliphatic dihydric alcohol compounds and lactide to obtain dihydroxy-terminal polylactic acid, and esterifying and polycondensing the aliphatic dicarboxylic acid compounds, aliphatic dihydric alcohol compounds, multi-element compounds and dihydroxy-terminal polylactic acid to obtain the aliphatic-polylactic acid segmented copolymer; or polymerizing polyol compounds and lactide to obtain polyhydroxy-terminal polylactic acid, and esterifying and polycondensing obtained polyhydroxy-terminal polylactic acid, the aliphatic dicarboxylic acid compounds and aliphatic dihydric alcohol compounds to obtain the aliphatic-polylactic acid segmented copolymer. The aliphatic-polylactic acid segmented copolymer contains branched aliphatic polyester chain segment, and a flexible chain segment is introduced, so that the flexibility of the aliphatic-polylactic acid segmented copolymer is improved, and the breaking elongation is improved; furthermore, the segmented copolymer has relatively high melt strength and is advantageous to molding processing of materials.