Abstract: Alkaline protease is one of the most important industrial proteases. To further improve its activity under high temperature alkaline conditions and enhance its industrial application values,the alkaline protease-encoding gene aprE539 was obtained by PCR amplification from Bacillus licheniformis CTCCC M2018539 and cloned into the expression vector pND-113 to express alkaline protease ApaE539 in Bacillus subtilis WB600 in this study. The recombinant AprE539 was purified by ammonium sulfate precipitation(30%~70%),dialysis,DEAE anion sepharose anion-exchange chromatography separating to obtain pur enzyme. And the molecular weight of the purified AprE539 was determined by SDS-PAGE. The experimental results were as follows:The molecular weight of the purified AprE539 was 30 kDa. The recombinant AprE539 had the maximum activity at pH11.0 and 65~70℃. It was stable at pH6.0~12.0 and remained about 70% of the activity after incubation at 60℃ for 1 h. Its activity was significantly enhanced with the existence of Cu²⁺,Mn²⁺,Ca²⁺ and Mg²⁺. Two amino acid residues difference were found between AprE539 and alkaline protease 2709. However their properties were different remarkably,which would lay a foundation for further exploring the differences of their enzymatic properties.