Abstract: By using immunocytochemical technique of streptavidin labelled peroxidase,calcitonin immunoreactive cells in the digestive tract mucosa of mandarinfish(Siniperca chuatsi), largemouth bass (Micropterus salmoides), nile tilapia (Tilapia nilotica),freshwater pomfret (Colossoma brachypomum), oriental sheatfish (Silurus asotus),yellow catfish (Pelteobagrus fulvidraco),ricefield eel (Monopterus albus) and northern snakehead (Channa argus) were located and compared morphologically. Results showed that calcitonin immunoreactive cells were not found in any part of digestive tract of mandarinfish, nile tilapla and largemouth bass, but could be found in different part of digestive tract of other 5 species of stomach-containing telosts. Positive reaction of calcitonin immunoreactive cell was found in all digestive tract of yellow catfish. No Posihve reaction was found in the intestine of ricefield eel and northern snakehead; but positive cells were found in their stomach and in the oesophagus of ricefield eel. Positive cells were seen in all part of digestive tract except oesophagus of oriental sheatfish. Positive cells were only seen in the oesophague of freshwater pomfret. In the intestine, most of immunoreactive cells show a long shuttle-shaped,expanded cell body, nucleus show vacuole-like, and there are two opposite cytoplasmic processes extending to the gut lumen and the basement membrane respectively. In the stomach, calcitonin immunoreactive cells show a short shuttle-shaped when they locate among the epithelial cells space; their shape is more thich and short, having a small and short cytoplasmic processe, showing often irregular in shape; they locate along the edge of gastric fundus gland.