Millimeter wave therapy has attracted much attention in the medical field due to its non-invasive, deep penetration, regulation of biological electromagnetic fields, and promotion of tissue repair. This paper aims to explore the application and mechanism of millimeter wave therapy in the medical field. By combining literature review and theoretical analysis, the mechanism of millimeter wave regulating physiological functions of the body through weak electromagnetic interaction is analyzed, and the technical principles and components of the therapeutic device are summarized. In addition, the research results and clinical application cases of millimeter wave therapy in relieving pain, reducing inflammation, and promoting cell regeneration are summarized. The results show that millimeter wave therapy has demonstrated good efficacy in various diseases, and the structure and technical solutions of the treatment device are becoming increasingly mature. The conclusion is that millimeter wave therapy has significant clinical value and broad application prospects, but it still needs to be continuously optimized based on current shortcomings. This paper provides theoretical support and practical guidance for the development and application of millimeter wave therapy technology, and has important reference value.