Objective,2,To explore the clinical efficacy of Bawei Shenqi Pill in the treatment of ankylosing spondylitis with deficiency of kidney yang.,Methods,2,Using a randomized， double-blind， placebo-controlled clinical trial， 80 patients of ankylosing spondylitis with deficiency of kidney yang were randomly divided into the treatment and the control group， 40 in each group. The treatment group was administered with the Bawei Shenqi Pill and meloxicam，while the control group was given the Bawei Shenqi Pill placebo and meloxicam， with a course of 12 weeks. TCM curative effect and TCM syndrome score， spinal pain score， spinal mobility index（occiput to wall distance， chest expansion， finger to floor distance and Schober test）， bath ankylosing spondylitis disease activity index（BASDAI）， bath ankylosing spondylitis function index（BASFI）， C reactive protein（CRP）， erythrocyte sedimentation rate （ESR） and scores of quality of life assessment scale were observed after the treatment.,Results,2,①There were 74 cases of this experiment completed， including 38 cases in the treatment group and 36 cases in the control group. ② The total effective rate of TCM in the treatment group and the control group were 92.1% and 36.1% respectively， and the two groups were statistically significant in clinical efficacy （,P,<,0.05）. ③ After treatment， the TCM syndrome scores of the two groups were improved （,P,<,0.05）； the difference scores of low back pain， low back stiffness， limited activity， mental fatigue， pale complexion and low back and knee soreness in the treatment group were better than those in the control group （,P,<,0.05）.④ After treatment， the spinal pain score was improved in both groups （,P,<,0.05）； the difference of the spinal pain score in the treatment group was significantly better than that in the control group （,P,<,0.05）.⑤ After treatment ，The spinal mobility index was improved in both groups （,P,<,0.05）； the difference scores of chest expansion and Schober test in the treatment group were better than those in the control group （,P,<,0.05）. ⑥ After treatment， BASDAI score and BASFI score in both groups improved （,P,<,0.05）； the difference of BASDAI score and BASFI score in the treatment group were better than those in the control group （,P,<,0.05）.⑦ After treatment， CRP in the treatment group was improved （,P,<,0.05）， but there was no significant change in the control group （,P,>,0.05）； there was no significant difference between the two groups （,P,>,0.05）. After treatment， there was no significant difference in ESR between the two groups （,P,>,0.05）. ⑧After treatment， the physiological function（PF）， role-physical （RP）， physical pain（BP）， general health（GH）， energy（VT）， social function（SF） in both groups and mental health（MH） in the treatment group were improved （,P,<,0.05）； The difference scores of GH， VT and MH in the treatment group was significantly better than those in the control group （,P,<,0.05）.,Conclusion,2,Bawei Shenqi Pill can significantly improve the clinical efficacy of TCM in patients with ankylosing spondylitis of kidney yang deficiency type， improve joint inflammation and joint function to a certain extent， and improve the quality of life.