Histology of digestive system and microstructure of the digestive tract of Cambrus clarkii Girard was studied by using optical and scanning electron microscopy.The results showed that the digestive system is composed of fore-gut,mid-gut,hind-gut and digestive gland.The epithelium of all parts of the digestive tract is simple columnar epithelium,bearing with chitin on the surface of epithelium.There are tegumentary gland and bundles of radiating muscle among the connective tissues below epithelium of esophau...