Abstract: Background　The domestic biosafety threats are increasing, and the current research on the ability of the medical support unit members in the biosafety defense task is limited. Objective　To explore the core capabilities of personnel in mobile medical support units for biosafety defense tasks, so as to provide reference basis and ideas for formulating a systematic, scientific, and comprehensive capability development path. Methods　From April to May in 2025, a purposive sampling method was employed to select 21 personnel from six military medical schools for semi-structured interviews on the core competencies of mobile medical support team members in biological defense missions. Based on modular theory and utilizing thematic analysis, the interview data were analyzed and themes were refined. Results　In biodefense missions, core competencies could be summarized into three main thematic modules and eleven sub-modules. The first module, basic professional competencies, includes emergency response capability, teamwork and collaboration, psychological adjustment, and environmental adaptability. The second module, specialized biodefense competencies, covered biosafety knowledge and skills, on-site resource management and optimization in biodefense operations, coordination and control of medical evacuation for bio-contaminated casualties, and the ability to perform rescue and treatment during biosafety incident simulations and real-world drills. The third module, technology integration and professional development, encompassed proficiency in applying cutting-edge artificial intelligence technologies, information technology collaboration and resource sharing, and a commitment to continuous learning and career advancement within the position. Conclusion　Based on the modular theory, this study extracts the core competency elements of biosafety defense tasks, which possess independence and reconfigurability. These elements provide a theoretical framework for modular grouping and precision training of mobile medical support team members under the task context of "peacetime-war integration and rapid response."