Entrepreneurial activities are the power source of promoting a country’s economic development and social progress. Entrepreneurial intention can well predict entrepreneurial activities. Based on the framework of integration analysis, this paper explores the external and internal factors that affect individual entrepreneurial intention. The binary logistic regression method was used to analyze 121,613 valid data samples from 48 countries in the 2018 Adult Population Survey (APS). The results show that entrepreneurial opportunity, entrepreneurial network, entrepreneurial ability, entrepreneurial attitude, and other internal and external factors have significant positive effects on individual entrepreneurial intention. At the same time, the interaction of internal and external factors has a significant positive effect on individual entrepreneurial intention. The interaction of internal and external factors also has significant positive impact on individual entrepreneurial intention. Individual willingness to start a business is influenced by multiple factors such as entrepreneurial network, entrepreneurial opportunity, entrepreneurial ability, and entrepreneurial attitude. It is a comprehensive balance of an individual’s possible risks, benefits, and abilities to start a business, and a comprehensive result of wanting to do something (external opportunities and network relations), ability (knowledge and skills), and daring to do something (risk attitude).