The invention provides a genetically engineered bacterium for producing a recombinant alkaline protease. A promoter with the nucleotide sequence shown in SEQ ID NO: 1 combined with a signal peptide and a bacillus clausii alkaline protease gene aprE construct a recombinant expression vector, and the recombinant expression vector is transferred into a bacillus subtilis host WB600 and finally electrically transferred into bacillus amyloliquefaciens CGMCC No.11218 to obtain the recombinant genetically engineered bacterium. The shake-flask fermentation activity of the recombinant alkaline proteaseproduced by the genetically engineered bacterium reaches 18000 U/mL, which is 2.52 times as many as that of an original promoter P43 and signal peptide SPSacB combination; in a 5L tank amplification experiment, the enzyme activity of the recombinant strain reaches 58,000 U/mL, and a foundation is laid for the industrial production of the alkaline protease.