Objective: To explore the relationship between subjective well-being, self-identity and Internet addiction disorder among undergraduates. Method: A survey research method was used among 200 undergraduates which includes IUS, SWLS, PANAS and self-identity scale. Results: positive emotion had significantly positive relationship with Internet addiction disorder, but not with self-identity; the relationship between negtive emotion and Internet addiction disorder was not significant; self-identity had significantly positive relationship with negtive emotion and life satisfaction, and significantly negtive relationship with Internet addiction disorder; Internet addiction disorder could significantly predict self-identity; the relationship between Internet addiction disorder and self-identity was moderated by negtive emotion. Conclusion: There is a significant relationship between Internet addiction disorder, self-identity and subjective well-being; Internet addiction disorder could predict self-identity, and negtive emotion could moderate the relationship between them.