Entrepreneurship has been gotten fruitful attentions all around the world, it also has become one of the most significant engines for both national economic and social growth. The internal factors, which are able to affect entrepreneur’s behaviors during the whole entrepreneurship life cycle, are gradually becoming a hot topic in both practical and academic research fields. Especially for some of the famous researchers, such as Melissa Cardon and Mitchell, J.R. are leading the academic research of the relation between entrepreneurial emotions (e.g., passion and fear) and behaviors. In this study, our objective is to understand how passion and fear effect student entrepreneur’s behaviors when they are running their businesses at the early stage of entrepreneurship. Moreover, semi structured interview has been chosen to collect qualitative materials for this Master thesis paper. In this case, eight student entrepreneurs from Linnaeus University in Vaxjo, Sweden who are studying and running their business at the same time, or have finished their study already but started their business while they were students are selected by us for doing the interview. Furthermore, we broadly discussed about different stages of entrepreneurship, also entrepreneurial passion and fear along with entrepreneurial internal emotions such as cognition, self-regulation, self-efficacy, persistence, which could influence student entrepreneurs’ behaviors to start up their business and afterwards. Finally, after empirical analyzing we found that the bright side of passion and fear have positive effects on student entrepreneurs’ behaviors, whilst the negative effects of passion and fear can hinder their behaviors during the early entrepreneurial process.