Objective To investigate the relationship between internet addiction and SIOSS score, and to examine the mediating role of impulsivity and the moderating role of mental health level. Methods A total of 393 college students were tested with internet addiction scale, Barratt impulsiveness scale-version 11, SIOSS and symptom checklist 90 to establish a moderated mediation model. Results After adjusted for age, internet addiction tendency had a positive predictive effect on SIOSS score (β＝0.523, P＜0.01). Impulsivity played a partial mediating role in the relationship between internet addiction and SIOSS score, with a mediating effect value of 0.087 (45.72%). The first half of the mediating effect of internet addiction→impulsivity→SIOSS score was moderated by mental health level (β＝－0.118, P＜0.001). The predictive effect of internet addiction on impulsivity was stronger in individuals with good mental health level (with the indirect effect value of 0.619 9±0.048 7) compared with the individuals with poor mental health level (with the indirect effect value of 0.439 5±0.048 5). Conclusion Internet addiction can increase SIOSS score by enhancing individual impulsivity, but this effect is more pronounced in individuals with good mental health and then affect SIOSS score.