The present invention relates to a novel method for preparing cabazitaxel from 10-deacetylbaccatin III, and a novel intermediate therefor, and more specifically, to: a method which allows cabazitaxel to be more easily prepared in a high yield and in a high purity within a short time compared with a conventional method by preparing cabazitaxel via a novel intermediate using 10-deacetylbaccatin III as a starting material, and thus is suitable for industrial mass production; and a novel intermediate therefor.