Objective: To explore the prevalence of ametropia in primary and middle school students in Kaiyuan, Honghe Prefecture, Yunnan Province, to provide a scientific reference for local prevention and control of juvenile myopia. Methods: In September 2021, 38 534 students from 76 primary and secondary schools in Kaiyuan, Honghe Prefecture, Yunnan Province, were selected. The students underwent vision inspection and computer optometry examination. Chi square test was used to compare the prevalence of myopia across gender grade, ethnic group and residence. Results: The prevalence of myopia in primary and secondary schools students was 40.0%, the prevalence of hyperopia was 17.7 %, and that of astigmatism was 21.2%. The prevalence of poor vision was 50.7%, and the total rate of wearing glasses was 17.2 %. The prevalence of myopia among girls (45.7%) was higher than that among boys (34.5%)( χ 2=520.68). The prevalence of myopia among students was higher in urban areas (50.1%) than rural areas (28.4%)( χ 2=1 882.13). The prevalence of myopia in grades 1-9 increased with school grade( χ 2 trend =7 151.41). Significant differences were observed in the prevalence of myopia( χ 2= 1 299.26 ), hyperopia ( χ 2=164.13) and astigmatism ( χ 2=1 091.37) among ethnic groups( P <0.01). Conclusion The prevalence of myopia and astigmatism in primary and middle school students in Kaiyuan, increases with school grade, and the prevalence of myopia varies among ethnic groups. For juvenile myopia prevention and control, attention should be paid to the effects of urban and rural differences, gender differences, and ethnic differences, in a scientific, effective and comprehensive manner.