Abstract： Objective： To observe the clinical effect of modified Diantu Decoction combined with moxibustion for diarrhea- predominant irritable bowel syndrome with spleen- kidney yang deficiency syndrome. Methods：A total of 116 cases of patients with diarrhea-predominant irritable bowel syndrome were selected as the study subjects and divided into the control group and the observation group according to the random number table method， with 58 cases in each group. The control group was treated with Trimebutine Maleate Capsules， and the observation group was treated with modified Diantu Decoction combined with moxibustion based on the treatment of the control group. Both groups were treated for four weeks. The Irritable Bowel Syndrome Symptom Severity Score(IBS-SSS) and syndrome scores of spleenkidney yang deficiency syndrome as well as the clinical effects in the two groups were compared. Results： The total effective rate was 94.83% in the observation group，significantly higher than that of 81.03% in the control group， the difference being significant(P＜0.05). Before treatment， there was no significant difference being found in the comparison of the IBS-SSS scores including abdominal pain，abdominal pain frequency， abdominal distension， degree of defecation satisfaction and impact on life between the two groups(P＞0.05). After treatment， the above scores in the two groups were decreased when compared with those before treatment(P＜0.05)，and each score in the observation group was lower than that in the control group(P＜0.05). Before treatment， there was no significant difference being found in the comparison of traditional Chinese medicine(TCM) syndrome scores including abdominal pain，soreness and weakness of waist and knees， lack of appetite， cold body and limbs between the two groups(P＞0.05). After treatment，the above scores in the two groups were decreased when compared with those before treatment(P＜0.05)，and each score in the observation group was lower than that in the control group(P＜ 0.05). Conclusion： Based on routine western medicine treatment， the additional application of modified Diantu Decoction combined with moxibustion for diarrhea- predominant irritable bowel syndrome with spleen-kidney yang deficiency syndrome can effectively improve symptoms，signs and TCM syndromes of patients，and enhance the clinical effect.