The invention provides a preparation method of a polylactic acid based medicine-carrying controlled release material. The method comprises the following steps: dissolving levorotatory polylactic acid into a benign solvent of the levorotatory polylactic acid to obtain a skin-layer spinning raw solution; dissolving a target drug and racemic polylactic acid into a benign solvent of the racemic polylactic acid to obtain a core-layer spinning raw solution; obtaining double-component skin-core type medicine-carrying long fibers by using a double-component spinning method; then removing the solvent and dividing the long fibers into short fibers, namely the polylactic acid based medicine-carrying controlled release material. With the adoption of the method, by utilizing the difference of degrading performances of the polylactic acid with different configurations, the controlled release carrier material which meets different medicine controlled release time and is matched with a plurality of types of drugs is prepared through selecting polylactic acid skin-core layer raw materials with different molecular weights and configurations to control the length of the fibers; the preparation process is simple and is convenient for industrialized production.