Abstract: In order to understand the effect of probiotics on activities of digestive enzyme, Tilapias were selected as our experimental animal.The Tilapias were fed with basal diet supplemented probiotics A, which contains Bacillus Subtilis and Photosynthetic bacteria. The activities of amylase、lipase and protease in the Stomach、Intestine and Hepatopancreas of Tilapias were determined. The results were as follows. (1) Feed coefficient ratio of experimental group decreased 16.91% and weight gain rate increased 7.98%. (2) Activities of amylase in stomach, intestinal and hepatopancreas in experimental group was significantly or extremely significant increased (p＜0.05 or p＜0.01).(3) Activities of lipase in stomach, intestinal and hepatopancreas in experimental group was significantly or extremely significant increased (p＜0.05 or p＜0.01).(4) Activities of intestinal trypsin in experimental group was significantly increased ( p＜0.05).