The invention relates to application of triclabendazole in preparation of drugs for treating breast cancer. According to the application of the triclabendazole in the preparation of the drugs for treating the breast cancer, the drugs for treating the breast cancer are tablets, granules, pills or capsules. Application of a triclabendazole composition in the preparation of the drugs for treating thebreast cancer is also included. Cancer cells of the to-be-treated breast cancer are MCF-7 or MDA-MB-231. The application has the advantages that the triclabendazole can induce apoptotic pyroptosis invitro and in vivo, and GSDME is cut by activated caspase-3 to generate GSDME-NT that take effects and forms vacuoles; the discovery suggests that the triclabendazole plays a role in cancer treatmentby inducing apoptosis of the cancer cells, specifically inducing GSDME-dependent apoptosis through the activated caspase-3 and at least partially through enhanced ROS/JNK/bax mitochondrial apoptosis pathways.