The job demands-resources (JD-R) theory has been widely applied to explore relationships between employees' job characteristics and performance, particularly in contexts of paid work. This study extends the application scope of the JD-R theory to unpaid research contexts among graduate students. Results of an online questionnaire survey with 914 research-oriented Chinese graduate students verified the dual processes proposed by the JD-R theory. Specifically, the graduate students' perceived stress led to emotional exhaustion and sequentially decreased their research career commitment; academic support fostered mastery approach and then increased the research career commitment. In addition, mastery approach played a significant mediating role in the relationship between academic support and research career commitment. The findings enhance the understanding of graduate students' research characteristics and performance and have implications for optimizing the research environment for graduate students and stimulating their motivation and commitment to research career.