Abstract: Due to swelling below the tarsal joints of both hind limbs, the 17-year-old mare had poor joint flexion and extension which led to long-term walking difficulties. In order to diagnose and treat the case, basic clinical examinations, laboratory examinations and traditional Chinese veterinary medicine examinations were used to confirm the diagnosis, and the treatment was carried out according to the diagnosis results. The results showed that western medicine diagnosed as rheumatoid arthritis, traditional Chinese veterinarian medicine diagnosed as wind-cold dampness arthritis（mainly caused by “cold”） accompanied by kidney-yang deficiency. Western veterinarian’s closed therapy was used in early treatment; although the symptoms were relieved, it was easy to relapse. Afterwards, acupuncture therapy and traditional Chinese herbal medicine therapy were used. After 5 treatments, the effect was significant and the symptoms were eliminated without recurrence. The results suggested that good therapeutic effects could be obtained by treating such diseases by traditional Chinese veterinary medicine.