Abstract： Objective： To observe the clinical effect of Shugan Jianpi Decoction combined with Trimebutine Maleate Capsules for diarrhea-predominant irritable bowel syndrome (IBS-D). Methods： A total of 102 cases of patients with IBS-D were divided into the control group and the treatment group according to the random number table method，with 51 cases in each group. The control group was treated with Trimebutine Maleate Capsules， and the treatment group was additionally treated with Shugan Jianpi Decoction based on the treatment of the control group. Both groups were continuously treated for four weeks. Traditional Chinese medicine (TCM) syndrome scores， and the levels of plasma cholecystokinin (CCK)，neuropeptide Y (NPY)，and substance P (SP) were compared between the two groups before and after treatment. The clinical effects， incidence of adverse reactions， and disease recurrence rates were compared between the two groups. Results：After treatment，the total effective rate was 92.16% in the treatment group， higher than that of 82.35% in the control group (P＜0.05). After treatment， TCM syndrome scores and the levels of plasma CCK and SP in the two groups were lower than those before treatment (P＜0.05)， and the levels of plasma NPY were higher than those before treatment (P＜0.05)； TCM syndrome scores and the levels of plasma CCK and SP in the treatment group were lower than those in the control group (P＜0.05)， the level of plasma NPY in the treatment group was higher than that in the control group (P＜0.05). There was no significant difference being found in the comparison of the incidence of adverse reactions between the two groups (P＞0.05). The disease recurrence rate was 2.13% in the treatment group， lower than that of 9.52% in the control group (P＜0.05). Conclusion： Shugan Jianpi Decoction combined with Trimebutine Maleate Capsules has a definite cureative effect in the treatment of IBS-D，which can improve gastrointestinal function and reduce disease recurrence rate，with high safety.