Abstract: A manufacturing method of a polylactic acid molded article includes implementing a granulating step and a forming step. The granulating step includes: mixing a polylactic acid material, a polylactic acid recovery material having a weight average molecular weight less than that of the polylactic acid material, and a crystallizing agent in an environment of 180? to 250?; carrying out a first molecular chains recombination of the polylactic acid material and the polylactic acid recovery material; and forming a polylactic acid composition after granulation. The forming step includes: filling the polylactic acid composition into a mold with an injection molding machine; carrying out a second molecular chains recombination of the polylactic acid composition in the mold; and forming the polylactic acid molded article after curation. The present disclosure also provides a polylactic acid composition.