This study explored the manifestation of multifaceted emotions, sources of emotions, and emotion regulation strategies of college EFL learners participating in digital collaborative academic reading projects. Data were collected through a vignette-based survey that was comprised of 19 episodes of authentic emotion-inducing scenarios among 72 Chinese EFL learners, supplemented by semi-structured interviews with 16 participants. While the results showed a relatively balanced distribution of positive and negative emotions, anxiety, nervousness, and happiness were found to be the top three most commonly experienced emotions. The study identified three sources of positive emotions including topic interest, experiencing mastery and achievement, and recognition from other groups. The findings also revealed factors inducing negative emotions in digital collaborative academic reading: reading difficulties, challenges in interacting with group members, low-quality feedback from external groups, online learning environment and technology issues, and time pressure. Furthermore, the study extended the literature on emotion regulation by developing a comprehensive taxonomy of six categories of strategies (i.e., co-regulation, cognitive change, response regulation, attention deployment, task-related regulation, and situation modification) tailored to the context of digital collaborative academic reading. These findings can offer practical guidance for enhancing social-emotional interactions in technology-enhanced collaborative academic reading.