Abstract: Objective:To study the correlation between psychosomatic sub-health symptoms and internet addiction disorders (IAD) among middle school students.Methods:Based on stratified,random cluster sampling,a questionnaire investigation was conducted among 2 910 students from 6 middle schools of Bengbu city,including demographic characteristics,multidimensional sub-health questionnaire of adolescents (MSQA) and Young internet addiction scale.Results:The prevalence of physical,psychical and psychosomatic sub-healthy symptoms of the middle school student was 13.6%,55.4% and 64.0% respectively,and the three types of sub-health symptoms increased with the ascending of grades.The prevalence of IAD among middle school students was 9.3%.Boys had a higher prevalence (11.2%) than girls (6.9%),and urban students (10.7%) had a higher prevalence than the rural ones (6.8%) (P<0.01).The prevalence of physical,psychical and psychosomatic sub-healthy symptoms in students with IAD was higher than that with no IAD or not using internet (P<0.01).Conclusions:Internet addition disorder contributes to the arising of sub-healthy symptoms in middle school students.