BACKGROUND: Internet is gradually reshaping adolescents' behaviors in China. It is important to identify the prevalence and risk factors to predict Internet addiction among adolescent psychiatric patients. METHODS: The survey was conducted among inpatient or outpatient adolescent patients with mental disorders. All participants were interviewed face-to-face and completed Young Internet Addiction Test and other relevant assessments. Binary logistic regression analysis was used to exam between-group differences of internet addiction. RESULT: The prevalence for internet addiction (mild to severe) in adolescent psychiatric patients was 80.2%, where the prevalence for "medium and severe internet addiction was 25.5%. Logistic regression analysis identified two independent predictors for "medium and severe internet addiction" including the total score of Adolescent Non-suicidal-self-injury (NSSI) Behavior Function Assessment Scale (ANBFAS) and the diagnosis of generalized anxiety disorder (GAD) (R =0.27, = .02 for total ANBFAS score, = .01 for GAD) in psychiatric adolescent patients. CONCLUSION: The prevalence of internet addiction is notably high among adolescent psychiatric patients in China. Coping for Internet addiction in adolescent psychiatric patients should conclude the coping of NSSI and GAD.