This experiment was conducted to investigate the effects of dietary corn starch supplemental level on growth performance, digestive enzyme activities and serum biochemical indices of common carp. Nine hundred common carp with the average body weight of(36.12±1.18) g were randomly divided into 5 groups with 3 replicates in each group and 60 fish in each replicate. The fish in those groups were fed with five experimental diets. In the five experimental diets, the protein level was in order of 32.0%, 30.0%, 28.1%, 26.2% and 24.2%, and the corn starch supplemental level was in order of 0(control), 6.5%, 13.0%, 19.5% and 26.0%. The experiment lasted for 9 weeks. The results showed as follows:seeing from growth performance, weight gain rate and specific growth rate in control group were significantly higher than those in other groups(P<0.05). Feed conversion ratio and protein efficient ratio in 26.0% corn starch group were significantly higher than those in control group(P<0.05). Dietary corn starch supplemental level had no significant effect on lipase activity in hepatopancreas(P>0.05). Foregut lipase activity in 13.0% corn starch group was significantly higher than that in 6.5% corn starch group(P<0.05). Midgut lipase activity in control group and 19.5% corn starch group was significantly higher than that in 6.5% corn starch group(P<0.05). Hindgut lipase activity in 26.0% corn starch group was significantly higher than that in 19.5% corn starch group(P<0.05). Hepatopancreas amylase activity in 26.0% corn starch group was significantly higher than that in other groups(P<0.05). In foregut, midgut and hindgut, the amylase activity in 6.5% corn starch group was significantly higher than that in other groups(P<0.05). The protease activity in hepatopancreas, foregut, midgut and hindgut was significantly decreased with the increase of dietary corn starch supplemental level(P<0.05). Serum glucose content showed an increasing trend with the increase of dietary corn starch supplemental level, and the difference was significant among all groups(P<0.05). Serum cholesterol content in 26.0% corn starch group was the highest, which was significantly higher than that in other groups(P<0.05); and it in 6.5% corn starch group was the lowest, which was significantly lower than that in other groups(P<0.05). Serum triglyceride content in 26.0% corn starch group was the highest, which was significantly higher than that in other groups(P<0.05); and it in 6.5% and 13.0% corn starch groups was lower, which was significantly lower than that in other groups(P<0.05). Comprehensive analysis of the measured indices, the digestive capacity of common carp can be raised by properly reducing protein level, and when dietary corn starch supplemental level at 0 to 13.0% and protein level at 28.1% to 32.0% are suitable for growth of common carp in this experimental condition.