Objectives: By observing and evaluating the clinical curative effect systematically of electrical acupuncture (EA) on Tianshu (ST 25) on diarrhea-predominant irritable bowel syndrome (D-IBS), to make it benefit for the application and spread of EA on Tianshu (ST 25)on D-IBS. Methods: 103 D-IBS matched the involved standards were allocated into treatment group (EA on ST 25, n=53) and control group (EA on Daheng, SP 15, n=50) in randomized,controlled and single-blind ways. Curative effect differences were analyzed by Ridit analysis.Results: The incidence of diarrhea, abdominal pain, abdominal distention or abdominal discomfort, borborygmus, defecation urgency and defecation incompletion feeling were 100%,89.3%, 71.8%, 74.8%, 83.5% and 78.6% respectively in D-IBS. Generally, after treatment, 11cases got excellent results, 34 cases improved and 8 failed in treatment group, totally effective rate was 84.9%; while in control group, 4 cases got excellent effects, 26 improved and 20 failed,totally the effective rate was 60.0%. Conclusion: Compared with control group, EA on Tianshu (ST 25) has a better curative effect on D-IBS.