To observe and evaluate the effectiveness and safety of Bushen Tongdu (reinforcing the kidney-yang and regulating the Governor Vessel) external treatment for patients with kidney-yang deficiency type ankylosing spondylitis (AS).Patients with Kidney-yang deficiency type AS were randomly divided into an observation group(36 cases, 4 cases dropped out) and a control group(36 cases, 3 cases dropped out). The observation group were received the Bushen Tongdu external treatment which was a combination of Ren Du Zhou-Tian moxibustion and acupoint embedding therapy, i.e. performing ginger-juice soaked nonwoven separated moxibustion first at the back covering the region from Dazhui (GV14) to Yaoshu (GV2) for 1 h, and then at the thoracoabdominal region covering the part from Tiantu (CV22) to Zhongji (CV3) for 1 h, followed by performing acupoint catgut embedding at one or two pairs of GV14, Shenshu (BL23), Dachangshu (BL25), Xuehai (SP10), and Zusanli (ST36), once a week, for 8 weeks. The control group received oral administration of salazosulfapyridine capsules (0.2 g/time), once a day for 8 weeks. Changes of the patients' conditions were evaluated by using traditional Chinese medicine (TCM) syndrome score (0 to 3 points for cold and painful lower back, morning stiffness, limited lumbar movement, soreness and weakness of waist and knees, etc.) and the total score (0 to 18 points), the Bath ankylosing spondylitis disease activity index (BASDAI) score (0 to 10 points for fatigue, physical discomfort caused by pain, swelling, or tenderness in the spine and peripheral joints, duration and severity of morning stiffness, etc). The therapeutic effect was assessed . The safety observation included fainting during acupuncture or moxibustion treatment, burn, etc. The contents of serum interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α), and matrix metalloproteinase-3 (MMP-3) were detected before and after the treatment.After 8 weeks of treatment, the TCM syndrome score, total score, BASDA score, contents of serum IL-6, TNF-α and MMP-3 were strikingly decreased in both groups compared with those of their own pre-treatment (P<0.05), and the therapeutic effect of the observation group was significantly superior to that of the control group in lowering the scores of cold and painful lower back, weakness in the lower back and knees, preference for warmth and aversion to cold, pain worsened by cold, and total score, BASDA score, and contents of serum IL-6, TNF-α and MMP-3 (P<0.05). The total effective rate of observation group was 90.63% (29/32), which was higher (P<0.05) than that of control group (75.76%, 25/33).The Bushen Tongdu external treatment method significantly improves AS patients' TCM clinical symptoms, alleviates inflammatory reactions, and demonstrates a significant efficacy with good safety.