In recent years, traditional Chinese medicine has made great progress in the treatment of diarrhea predominant irritable bowel syndrome (IBS-D) in clinical and experimental research. In this paper, the mechanism of traditional Chinese medicine treatment of this disease was summarized. Methods:The impact of traditional Chinese medicine (TCM) on the brain gut amine (peptide) and neurotransmitter expression, the content and related inflammatory factor change were our major interests when conducting literature review on published literature home and abroad in recent five years. Results:The main mechanism of TCM is：lowering the content of 5-HT in colonic mucosa and blood, reducing the expression of vasoactive intestinal peptide (VIP) and secretion, increasing the NO level in the intestinal tissue, reducing gastric dynamic element (MOT) in plasma, glucagon like peptide 1 (glp-1) and somatostatin (SS), the content of substance P (SP), reducing the number of mast cells and nerve immunity mechanism activation, regulation of pro-inflammatory factor and anti-inflammatory factor levels. Conclusion:The mechanism research should be further enhanced to reveal the physiological and pathological mechanism of TCM treatment.