Abstract: Objective To explore the characteristics of histopathology,ultrastructure and histochemistry and changes of DNA ploidy of gastric carcinoid tumors. Methods Eight cases of gastric carcinoid tumors were studied by microscope,electron microscope,AB-PAS stain,Masson Fontana stain,and Grimelius stain,and also by image analysis system for DNA ploidy. Results Microscope observation showed characteristic histopathological change,AB-PAS stain showed moderate to severe intestinal metaplasia of stomach mucosa.All of cases showed negative of Masson Fantana stain,and six cases showed positive argyrophilic staining granules of Grimelius stain in carcinoid cytoplasm.Ultrastructurally,there were numerous dense-core pleomorphic secretory granules scattered throughout the cytoplasm.A large number of carcinoid cells were diploid and tetraphoid by means of DNA ploidy analysis. Conclusion “Classic” gastric carcinoid tumor was diagnosed only by histopathologic observation,but diagnosis of“non-classic” gastric carcinoid tumor also need to use other pathologic techniques such as electron microscope,etc.