Abstract: Objective To quantify the prevalence of Internet addiction disorder among middle school students since 2011 in China. Methods Publications were retrieved from China National Knowledge Infrastructure(CNKI), Wanfang Databases, Chinese Science and Technology Journal Databases(VIP) and PubMed. Observational studies on prevalence of Internet addiction disorder were included. Meta-analysis was carried out by using Stata 14 software. Results A total of 25 papers were included in this Metaanalysis. The total number of students investigated was 72 832, with 6 859 Internet addiction disorder identified. Based on Internet Addiction Scale Ⅰ(Xingyi compiled, 10 items, more than 5 points are evaluated as Internet addiction), Internet addiction scaleⅡ (Xingyi compiled, 10 items, conform with the first item and more than 4 points of the other 9 items are evaluated as Internet addiction) and Internet addiction scale Ⅲ(Young KS compiled, 20 items, more than 50 points are evaluated as Internet addiction), the prevalence of Internet addiction disorder in Chinese middle school students was 10. 78%(9. 19% - 12. 48%), 6. 92%(4. 72% - 9.51%) and 10.37%(7.62%-13.49%), respectively. The prevalence was higher in boys than in girls. No significant differences were found between junior school students and senior school students. Conclusion The prevalence of Internet addiction disorder is high among Chinese middle school students, especially among boys. No difference is found between junior and senior middle school students.