Collaborative learning group in higher education is increasingly supported by communication tools, but there are still some problems regarding engagement. We examined students’ engagement in collaborative learning groups with the help of communication tool—Slack. Students’ motivation to engage in teamwork can be promoted through the openness of team members’ effort on Slack. Moreover, free-rider and sucker effect can also be relieved. Teamwork engagement can prompt students’ learning and work satisfaction. We proposed a research model and corresponding hypotheses. Surveys were issued online to graduate students at different time of our course. SmartPLS 3.0 was used to analyze data and test structure equations. We came to conclusions lastly as follows: mutual trust, social influence and reward valence are positively related to teamwork engagement, and teamwork engagement is positively related to personal success (i.e. learning and work satisfaction). However, the moderation role of task complexity between teamwork engagement and personal success is not supported. Theoretical and practical contributions are discussed. Research limitations and future research directions are also presented.