Abstract: ObjectiveTo study the prevalece of internet addiction disorder(IAD)and its influencing factors among adolescent students in Chongqing city and to provide bases for intervention measures.MethodsThe Internet Addiction Scale(IAS)was adopted in the study to test 3968 adolescent students randomly sampled in Chongqing.ResultsOf the students,9.8% had internet addiction.The rate of internet addiction was higher in the male than that in the female,and the rate of internet addiction in internet users of city school was higher than that of rural school.The rate was also higher in internet users who were left behind by parents working out than the control students.Stepwise logistic regression analysis indicated that female,having many friends,family in rural area were the protective factors,and grade,using intemet for many time per week,behavior of suicide,heavy loads of study were the risk factors for IAD(P<0.05).ConclusionThe adolescents are high-risk population of internet addictive behavior.Intervention activities should be carried out by education,health agency and students'parents.