Abstract: This paper summarized Bacillus licheniformis characteristics,function,as well as the mechanism of action and the application actuality in aquaculture,and pointed out the problems during production practice and future research directions.B.licheniformis is a gram-positive facultative anaerobe.It has the characteristics of acid-resistant,heat-resistant,bile salts tolerance and artificial gastric juice tolerance,which have a great application prospect in aquaculture.In aquaculture,it has the function of maintaining the ecological balance in the intestine,promoting the absorption of nutrients,improving the immunity of the organism and purifying the water environment.The scientific use of B.licheniformis can promote the healthy development of aquaculture.