Abstract: Objective To examine the prevalence and heritability of myopia among Uygur and Han students in Urumqi city of Xinjiang Uygur Autonomous Region(Xinjiang).Methods By using cluster sampling,2 380 Uygur and Han students were selected from middle schools in Urumqi city of Xinjiang and a questionnaire survey and myopia screening were conducted among the students.The heritability of myopia for first- and second-degree relatives among the students was calculated with Falconer method.Results The overall prevalence rate in myopia was 60.12% in the students;the prevalence rate in the Uygur students was significantly lower than that in the Han students(37.80%vs.77.36%,P<0.05) and the prevalence rate in the boys was significantly higher than that in the girls among both the Uygur students(31.31%vs.42.08%,P<0.05)and the Han students(71.61%vs.82.40%,P<0.05).The prevalence rate of myopia among the first-degree relatives was 10.23%in the Uygur myopia students,which was higher than that in the Uygur students without myopia(4.87%,odds ratioOR=1.921)and the myopia prevalence rate among the first-degree relatives was 18.90%in the Han myopia students,which was higher than that in the Han students without myopia(10.82%,OR=2.225);with the first-degree relatives of myopia was a risk factor of suffering myopia in the students.The heritability of myopia for first-degree relatives was 36.86%for the Han students and 36.27%for the Uygur students.Conclusion The etiology of myopia is very complicated and the prevalence of myopia results from the combined effects of multiple genetic and environmental factors among middle school students.