Abstract: By using microscopy and electron microscopy,morphological characteristics of cells involved in intestinal mucosal im2munity in the Chinese soft2shelled turtle, Trionyx sinensis, were examined in detail,and,as a result,the nature of the mucosalimmune response in the reptile was discussed1Epithelial cells in the intestinal mucosal arranged loosely along the intestinal mu2cosal membrane,especially in large intestine,and there were manyobvious spaces between the epithelial cells1Intraepithelial lym2phocytes (IEL) and plasma cells were widely distributed in the intestinal mucosal epithelium1The number ratio of the IEL in up2per2nucleus region,nucleus region and lower2nucleus region of the epitheliumwas 4∶ 3∶ 31In upper2nucleus region1small lympho2cytes dominate while in nucleus and lower2nucleus regions,the volume of the lymphocyte becomes a little bigger and several largegranules occurred in each cell1IELs located in spaces of the epithelium,some of which protrude pseudopods inside the epitheliumand some were seen in the lumen of the intestine1In the nucleus region and lower2nucleus region of the epithelium, there weremany plasma cells locating between the epithelial cells,in which the dilated rough endoplasmic reticulum were filled up1Laminapropria lymphocytes (LPLs) 、 plasma cells、 macrophages,and some leucocytes dispersed in the lamina propria1In intestinal villi,the lymph nodule was not observed although LPLs sometimes dominated the villi1The structure of the LPL was generally like thatof IEL1In the lamina propria,there were two types of plasma cells,one has the dilated rough endoplasmic reticulum and the otherdoes the parallel one,and the former type dominate in number1The results sugested that the mucosal immune reaction mechanic ofthe reptile was different in some ways from the mammalian and bird which have M cells in the epithelium and lymph nodules inthe lamina propria1