Abstract: To elucidate the effects of replacing soybean meal protein with corn DDGS on the growth performance, body composition, antioxidant capacity, and histology of the digestive system of juvenile Cipangopaludina cathayensis, four iso-nitrogenous and iso-caloric diets were formulated to feed juvenile Cipangopaludina cathayensis with the average initial body weight of (3.60±0.01) g for 56d. The inclusion levels of corn DDGS were 0, 13.63%, 27.26%, and 40.89% by using corn DDGS instead of soybean meal protein in different proportions 0 (D0), 25% (D25), 50% (D50), and 75% (D75), respectively. The results showed that: (1) FBW, SGR, and WGR in the D25 group were significantly higher than those in the D0 group (P<0.05). However, no significant differences were found in the SR, FR, FE, and PER between the D0 and D25 groups (P>0.05). Compared with the D0 group, the FBW, SGR, and WGR in the D50 and D75 groups were significantly reduced (P<0.05). In the D25 group, the crude protein, crude lipid, and ash content in juvenile Cipangopaludina cathayensis were markedly higher compared to those in the D0 group (P<0.05). The trypsin (TPS) and lipase (LPS) activities in hepatopancreas and intestine of the D50 and D75 groups were significantly lower than those in the D0 group (P<0.05), while no significant change occurred in amylase (AMS) activity among all the groups (P>0.05). (2) Hepatopancreatic and intestinal alkaline phosphatase (AKP), acid phosphatase (ACP), catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx), and glutathione S-transferase (GST) activities of the D25 group showed no significant differences compared with the D0 group (P>0.05). The activities of CAT, SOD, and GPx in the hepatopancreas and intestine were significantly lower in the D50 and D75 groups than those of the D0 group (P<0.05), while the content of malondialdehyde (MDA) in hepatopancreas and intestine of the D75 group was significantly higher than that of the D0 group (P<0.05). The expression levels of GPx, GST, and SOD genes in hepatopancreas, as well as GST gene expression in intestine, decreased significantly in the D50 and D75 groups compared with the D0 group (P<0.05). (3) There were no significant differences in the hepatopancreatic and intestinal tissue structure between the D25 and D0 groups. However, in the D75 groups, the partial hepatic tubular structure of the hepatopancreas was disordered, and the basal membrane was ruptured. The intestinal epithelial cells of the D50 and D75 groups were damaged and the lamina propria atrophied. In conclusion, the proportion of corn DDGS in juvenile Cipangopaludina cathayensis feed should not exceed 13.63%.