Abstract: Bacillus licheniformis and its related strains have a wide range of applications in industry, agriculture and medicine. At present, the main methods of strain selection are natural screening and traditional mutagenesis. However, due to the lack of efficient gene editing tools, further expansion of the application of B.licheniformis is limited. In this study, the recombinant protein RecT derived from Bacillus phage 049ML001 was identified as a potential recombinant enzyme, and a homologous recombination system for conditional expre-ssion of the recombinase was constructed by using the rhamnose-inducible promoter P_rha. The recombination efficiency of the system was further improved by optimizing the action conditions of the recombinase. The results showed that rhamnose induction concentration, time and strain passage times were important factors affecting the recombination efficiency. The wild-type bacteria were transformed with recombinant plasmids, and 1.5% rhamnose was added to induce the expression of the recombinase RecT after 8 h of growth. The recombination efficiency reached 16.67% after culturing for 24 h and three passages. In contrast, the parental bacteria could not achieve recombination. In this study, the recombination system based on the conditional expression of the recombinase RecT significantly improved the recombination efficiency of B. licheniformis, and provided an effe-ctive gene editing tool for the construction of genetically engineered strains and bacterial physiology research.