By using the strept avidin biotin-peroxidase complex( SABC) immunocytochemical staining technique, the immunoreact ive endocrine cells in the esophagus, cardia, fundus ventriculi, pylorus, foregut, midgut, hindgut, pancreas and liver of oriental sheatfish( Silurus asotus ) and yellow catf ish( Pelteobagrus fulvidraco) were localized with 2 kinds of antisera-gonadotropin releasing hormone ( GnRH) and gonadotropin releasing hormone receptor( GnRHR) . The result showed that there was GnRH and GnRHR immunoreactive positive reaction in the esophagus, stomach, intestinum, membrana propria, nerve plexus in myenteron, pancreas and pancreatic island of S. asotus and in the digestive system of P. fulvidraco, and the immunoreactive positive reaction of GnRH and GnRHR was also found in all parts except in the esophagus and pancreatic island, and the distributive patterns of GnRH and GnRHR are similar. It is suggested that the GnRH in the gastrointestinal tract may participate in modulation the digestive function via autocrine or paracrine mechanism. It is demonstrated for the first time that there are GnRH and GnRHR immunoreactive endocrine cells in the digestive system of fishes. It provided new morphological basis for the research f ield of the functional diversity of GnRH.