In recent years, live streaming has become the mainstream way of online shopping in China. As the dominant player and performer in live streaming, streamer plays a crucial role in consumers’ purchase decisions. Therefore, this study focuses on the self-presentation behavior of streamers in the context of e-commerce live streaming and explores the mechanism of its influence on consumers’ purchase intention from the perspective of persuasion knowledge. A total of 538 consumers from China participated in this anonymous survey and the results indicate that helpful and empathetic behaviors of streamers can significantly enhance consumers’ purchase intention, while derogatory, exaggerated, and flattering behaviors of streamers can significantly diminish consumers’ purchase intention. Persuasion knowledge played a mediating role and had a significant negative effect on purchase intention, while anticipated inaction regret weakened its effect on purchase intention.