Abstract: In the present experiment, the effects of Debaryomyces hanseni, Bacillus subtilis and Bacillus coagulans (3.01011 cfu/kg feed) on growth and the digestive enzyme activities of Oreochromis niloticusO. aureusaverage initial weight about (34.500.25) g for 56 days were studied. The results showed that compared with the control group (non-supplemented), the weight gain rates of Bacillus subtilis and Bacillus coagulans were 12.27% and 8.18%, which were higher than that of the control (P0.05). The feed coefficients of Bacillus subtilis and Bacillus coagulans were 10.92% and 8.18%, which were lower than that of the control respectively (P0.05). Compared with the control group, the apparent digestibility on dry matter of Bacillus subtilis and Bacillus coagulans increased by 10.54% and 10.07%, and the protein apparent digestibility increased by 4.18% and 3.65% (P0.05). Bacillus subtilis and Bacillus coagulans adding to the diets could significantly improve the activities of proteinase in intestine, hepatopancreas and stomach of Oreochromis niloticusO. aureus (P0.05) compared to the control group and Debaryomyces hanseni group, but three Micoecologics adding to the diets showed no significant difference with the activities of amylase and lipase in intestine, hepatopancreas and stomach of Oreochromis niloticusO. aureus (P0.05). The results suggested that diet with 3.01011 cfu/kg feed of Bacillus subtilis supplement could significantly promote the growth of Oreochromis niloticusO. aureus and the activities of proteinase in intestine, hepatopancreas and stomach of Oreochromis niloticusO. aureus.