Provided is a method for preparing a poorly water-soluble drug-containing polymeric micellar nanoparticle composition, which includes: dissolving a poorly water-soluble drug, a salt of polylactic acid or polylactic acid derivative, whose carboxylic acid end is bound to an alkali metal ion, and an amphiphilic block copolymer into an organic solvent and adding an aqueous solution to the resultant mixture in the organic solvent to form micelles, wherein the method requires no separate operation to remove the organic solvent prior to the formation of micelles. The method for preparing a poorly water-soluble drug-containing polymeric micellar nanoparticle composition is simple, reduces the processing time, and is amenable to mass production.
