Based on the theory of entrepreneurial cognition, we examined the relationship between entrepreneurial passion and opportunity identification, and the moderating roles of environmental complexity and mediating role of entrepreneurial contextual knowledge in this relationship. Results from 246 entrepreneurs supported the hypothesis that both their entrepreneurial passion and their entrepreneurial contextual knowledge would be positively related to opportunity identification, and these relationships would be moderated by environmental complexity. Further, environmental complexity enhanced the relationship between entrepreneurial passion and opportunity identification, and also amplified the relationship between contextual knowledge and opportunity identification. The results suggest that the effect of entrepreneurs’ passion on opportunity identification depends on the level of the individual's contextual knowledge and environmental complexity.