A solid dispersion of dutasteride for improving the solubility or dissolution rate of poorly soluble dutasteride, a method for preparing the solid dispersion, and a pharmaceutical composition including the solid dispersion are provided. The solid dispersion includes: a coprecipitate including dutasteride and a water-soluble polymeric carrier； and an adsorbent. The dutasteride and the water-soluble polymeric carrier are present in a weight ratio of 1:10-100 in the coprecipitate. The solid dispersion exhibits a dissolution rate equal to or higher than AVODART® soft capsules and contains a minimal amount of related substances, achieving good storage stability.
