Abstract: A 13-year-old female Chinese garden dog, weighting 6 kg, had breast tumors one year before treatment, and did not use medication; about half a year ago, the tumor grew faster, and it started to take Tuoxiaohualiu capsule. About one month ago, the breast appeared swelling and ulceration. It used topical ointment, but it didn’t get better. In order to diagnose and treat the disease, the methods of medical history, general clinical examination, laboratory examination and imaging diagnosis were used for initial diagnosis, and histopathological diagnosis was confirmed; and the treatment was carried out based on the diagnosis results. The results showed that the dog’s disease was inflammatory mammary carcinoma, which was the most malignant of all breast tumors. Right total breast resection and left third, fouth and fifth breast tumor resection as well as hysterectomy and oophorectomy were performed. The dog relapsed at seven months after surgery and died at ten months. The results showed that inflammatory mammary carcinoma had a greater impact on dogs, and the prognosis was cautious.