Objective To study the efficacy and safety of Bushen Qiangdu Recipe（ BQR

补肾强督方） combined with sulfasalazine in the treatment of ankylosing spondylitis（ AS）. Methods Totally of 60 AS patients were randomly and equally assigned to the treatment group and control group. The treatment group received BQR twice a day and sulfasalazine 2 g daily for 3 months. The control group received only sulfasalazine 2 g daily for 3 months. The Assessment in Ankylosing Spondylitis 20（ ASAS 20）

Bath Ankylosing Spondylitis Disease Activity Index（ BASDAI）

Bath Ankylosing Spondylitis Functional Index（ BASFI）

Bath Ankylosing Spondylitis Metrology Index（ BASMI）

patient’s general assessment

spinal pain

general pain and night pain were used for scoring（ 1-10） patients with AS.A higher score indicated a more severe illness stage. Physical examination

blood and urine tests

erythrocyte sedimentation rate（ ESR） and C-reactive protein（ CRP） measurement were performed at each visit. Results A total of 57 patients completed the study. There were 29 patients in treatment group and 28 patients in control group. There was less side effect in the treatment group than that in the control group. After treated by combined medicine and sulfasalazine

the proportion of ASAS20 responders at 3 month was 82. 75%（ 24/29） and 71. 43%（ 20/28） respectively. Both combined medicine and sulfasalazine treatment induced significant decrease in the proportion of expressing ESR and CRP at 3-month of treatment compared with baseline values（ P < 0. 05）. The effective rate in the treatment group was significantly higher than that in the control group. Conclusion Combined treatment of BQR and sulfasalazine could improve the symptoms and inflammation level of AS and it showed better effect and safety than sulfasalazine alone.