Abstract: Idiosyncratic deals is personalized work arrangements accomplished through negotiation between enterprises and employees based on the ability and needs of employees, which is an important tool with high-efficiency in modern human resource management practice. Under the framework of social exchange theory and social cognition theory, this study explores the mechanism of how different types of idiosyncratic deals take effects on knowledge sharing behavior through organization-based self-esteem with the moderation of emotional relationship. Our research findings show that the task and development idiosyncratic deals can promote knowledge-sharing behaviors through improving organization-based self-esteem. Employee emotional relationships moderate the positive effect of organization-based self-esteem on knowledge sharing behavior. In the meanwhile, employee emotional relationships moderate the indirect effects of idiosyncratic deals on knowledge sharing behavior through organization-based self-esteem.