Open-source software (OSS) development is leading trends in the software market. OSS teams occupied with knowledge-intensive tasks are confronted with role-related issues. Team-level role dynamics (i.e., role ambiguity and role conflict) which manifest whether information about roles (e.g., expected responsibilities, behaviours, and outcomes) perceived by members are clarified and coherent, affect team performance. Information about roles can be considered clues for expertise recognition and location, which strengthens members’ reliable understandings about others’ knowledge and work cooperation. Namely, it may influence transactive memory system (TMS), a group work pattern based on cognitive labour division. Although prior studies have proposed that role-related constructs (e.g., role identification, and role conflict) influence team cognitions (e.g., TMS) and team performance, the relationships between role dynamics, TMS and team performance are still unclear. This study intends to explore the affective and cognitive mechanism through which role dynamics influence TMS under various boundary conditions (i.e., instrumental and expressive communication), and provides a further understanding about how to enhance team performance within the mechanism. An empirical study sampling from OSS communities like SourceForge and GitHub will be conducted to verify our hypotheses. Our research intends to offer theoretical and managerial implications about role concerns in OSS teams.