Abstract: The quality of pre-departure preparation of complete-formation health emergency teams for overseas assistance directly determines the response efficiency and on-site operational effectiveness in cross-border rescue missions. Taking the post-disaster epidemic prevention assistance mission undertaken by the National Mobile Health Emergency Center for Infectious Diseases (Yunnan) for the earthquake in Myanmar on March 28, 2025 as a case, this paper systematically sorts out the core elements of the pre-departure preparations of emergency medical teams for overseas missions and conducts an in-depth analysis of the key practices in key links including member selection and team assembly, material integration and international transportation. In response to the practical challenges, such as the superposition of safety risks, fragility of resource supply, and cross-cultural communication barriers, faced in cross-border rescue, this paper proposes countermeasures including procedural and modular management of pre-departure preparation, institutionalized and normalized multi-department emergency coordination and linkage mechanisms, and standardized and integrated material development for health emergency teams, aiming to provide theoretical references and practical models for the pre-departure preparations of complete-formation health emergency teams for overseas assistance missions.