The present invention relates to a method for preparing an itraconazole-containing solid dispersion. The itraconazole-containing solid dispersion according to the preparing method of the present invention has both improved solubility and rapid dissolution rate so that it has an excellent bioavailability. The itraconazole-containing solid dispersion of the present invention is also independent of pH variation of human stomach so that it can minimize the absorption variation of intra- and inter-individuals. In addition, the itraconazole-containing solid dispersion according to the preparing method of the present invention is stable for a long time. The present invention also provides an economical and environment-friendly method for manufacturing an itraconazole-containing composition because the method adds a lactic acid in a solution comprising itraconazole to decrease the amount of an organic solvent needed to dissolve itraconazole.