Abstract: Digestive enzyme activities of grass carp fed with two test diets were studied at 0,5,10 and 15 hours over a period of two weeks.The experiments showed that intestinal protease activity in the fish meal group reaches a maximal level 10 hours after feeding,but in the case of the soybean meal group,the peak appears at the 15th hour.Amylase activity reaches a maximun at 10 hours for both fish meal and soybean meal groups.Hepatopancreatic protease activity decreases immediately after feeding,drops to its minimum after 5 hours,and then increases gradually.In the case of amylase,similar changes are noticed,though they take place more slowly. In conclusion,the activities of protease and amylase in the fish meal group are higher than those in the soybean meal group.The protease activity is highest in the fore intestine and lowest in the hind intestine.