Objective: To investigate the effect of group psychotherapy on middle school students with internet overuse (IOU). Methods: A total of 2620 middle-school students from four middle schools of Changsha City were surveyed using Diagnostic Questionnaire for Internet Addiction (YDQ), According to the YDQ criterion and clinical interview, 64 students who were diagnosed as Internet overuse. 29 middle school students with IOU from one regular middle school and one key middle school received group psychotherapy. 35 middle school students with IOU from the other two schools were taken as control (control group). All the students in both groups were assessed with Diagnostic Questionnaire for Internet Addiction (YDQ), Chen Internet Addiction Scale (CIAS), The Screen for Child Anxiety Related Emotional Disorders (SCARED), Strength and Difficulties Questionnaire (SDQ). Results: The scores Of SCARD and SDQ subscale of emotional symptoms of experimental group decreased significantly (t = 2.11-2.99, P < 0.05-0.01) after treatment. The scores Of YDQ and CIAS of experimental group decreased significantly (t = -8.083, -4.383, P = 0.000) after treatment, the significant improved clinical effect rates and total effect improved rates were 57.69% and 76.92% respectively. The scores Of YDQ and CIAS of experimental group were lower than that of control group after treatment (t = 4.16, t = 5.16, P = 0.000). Conclusion: The group psychotherapy can significantly reduce IOU and improve psychological function showing in profiles of SCARD for the middle school students with IOU.