Objective To explore the animal model making method for diarrhea-predominant irritable bowel syndrome （IBS-D） caused by the disharmony of liver and spleen in TCM.Methods In order to define the period of the animal model making

the 32 neonatal rats were divided into 3 days group

6 days group

9 days group and control group.In order to determine the weight of the experimental rats

the 48 rats with different weight were divided into lower weight model group

lower weight control group

medium weight model group

medium weight control group

higher weight model group and higher weight control group.In order to decide the method of causing diarrhea

the 32 rats were divided into lactose enriched diet group

restraint stress group

lactose enriched diet plus restraint stress group

and a control group.The body weight and diarrhea rate of all groups were compared respectively.After the method of model making was decided

the 16 rats were divided into a model group and a control group

and 5-hydroxytryptamin （5-HT）

lactate dehydrogenase （LDH） and aquaporin 4 （AQP4） of the two groups were compared for model-proving.Results Based on the results step by step

the best method was decided:the period of the animal model making was 6 days

rats with higher body weight should be subjects

and the lactose enriched diet combining with restraint stress should be used to induce diarrhea.Model-proving test:compared with the control group

5-HT and LDH decreased （P<0.01

P<0.05） and AQP4 increased （P<0.05） in the model group.Conclusion The animal model has the symptoms of gastrointestinal system

and its pathological changes relate to emotion.So it can be used in the experimental study of IBS.