Purpose: This study aims to recognize the key successful factors of korea hospital overseas expansion through the current registration cases of hospital expansion and shed light on the future enhancement strategy to make us of Diamond model theory by Michael Porter and analysis of STP. Research design, data, and methodology: It is purposed to look into not only the key factors and demand condition by case analysis, also elements of government police, investment and competitiveness factors by hospital industry to analyze the hospital expansion types, finally make determine the market segmentation, target and positioning so as to propose the future strategy for oversea expansion. Results: This study analyzed the success factors of overseas expansion of medical services and tried to present significant results with basic data from the perspective of research on future overseas expansion of medical services. Implications: This study analyzes the success factors that are steadily increasing in Korea’s medical overseas expansion based on the total number of overseas medical entry notification systems from the government to 2021. To this end, we analyzed the success factors for medical overseas expansion through Michael Porter’s Diamond Methodology and STP strategy to analyze market segmentation, targeting, and market positioning for medical overseas expansion. Finally, through the analysis of the success factors of medical overseas expansion, we wanted to deal with the future challenges of medical overseas expansion.