Compared to various other types of entrepreneurships, high-tech entrepreneurships are the most difficult to succeed in, but the rewards can be great. For startups, identifying customers and markets are as important as developing a product. Given the limited scale of domestic markets, if a high-tech startup wants to become a unicorn company, it goes without saying that entering international markets is necessary. This study considers high-tech startups as the research object. Through literature review, it first summarizes five major dimensions and 15 criteria. Then, it conducts the preliminary questionnaire survey on the effects of firm competencies and industry environment on internationally successful high-tech startups using expert questionnaires. The questionnaire survey was also used to establish the hierarchical structure and key success factors (KSF). Subsequently, the study conducted survey and statistical analysis of the questionnaire data using analytic hierarchy process (AHP). By assessing the dimensions and summarizing the key success factors, this study can serve as a useful reference for future startups. Existing startups can examine their own conditions and opportunities to reconsider their strategic positioning. Additionally, the findings of this study can support high-tech startups to enable them to concentrate on their core competencies in order to strengthen competitiveness and likelihood of success in international markets.