Alkaline protease has been commercially used in the areas of detergents, food and agriculture, and improving the performance and production of alkaline protease serves as an important role in promoting its market expansion. Here, an alkaline protease AE0 from Alkalihalobacillus clausii FYX was firstly characterized in Bacillus licheniformis DW2△aprE, the optimal temperature and pH of AE0 were 60 °C and 10.5, the K