The present invention relates to the use of chidamide and exemestane in the preparation of a combination medicament for the treatment of breast cancer, a pharmaceutical composition or a combination drug comprising chidamide and exemestane, and a method of treating breast cancer by combination use of chidamide and exemestane.本發明涉及西達本胺與依西美坦在製備用於治療乳腺癌的聯合用藥物中的用途、包含西達本胺與依西美坦的藥物組合物或聯合用藥物以及聯用西達本胺與依西美坦治療乳腺癌的方法。