The ultrastructure of the epithelium of digestive tracts in Carassius auratus gibelio was examed by transmission electron microscopy.The inter relationship between the ultrastructure and their functions were discussed. The mucosal epithelium of posterior esophagus consisted of columnar cells and mucous cells.Esophagus participated the absorption of water and ions.Columnar absorping cells and goblet cells were present in the epithelium of the intestine.The enterocytes of the anterior portion show evidence of Lipid absorption. The enterocytes of the posterior intestine exhibited the typical ultrastructral features of pinoctosis.