Objective: To understand the prevalence of myopia among primary and secondary school students in minority areas of Yunnan Province, and to explore the influence of outdoor activities and short-distance use of eyes, so as to provide a basis for early myopia intervention. Methods: In October 2020, the survey was conducted among 1 782 primary and secondary school students in three cities of Yunnan through a multi stage random cluster sampling method. All subjects underwent a questionnaire survey and the visual acuity examination at baseline. The first follow-up was conducted in October 2021 to obtain 1 691 valid samples, and the second follow-up was conducted in May 2023 to obtain 1 367 valid samples. Factors associated with myopia among primary and secondary school students were explored by using generalized estimating equations. Results: The prevalence rates of myopia in 2020, 2021 and 2023 were 52.64%, 61.62% and 69.35%, respectively, showing an increasing trend ( χ 2 trend =91.77, P <0.05). The results of multivariate regression analysis on the generalized estimation equations showed that age at baseline ( OR =1.31), girls ( OR =1.76), Hani ethnicity ( OR =0.75), Bai ethnicity ( OR =0.69), parental myopia ( OR =1.97-2.29), parents often reducing children s exercise time for homework or tutoring ( OR =1.35), less than 1 time or 2-3 times of ball sports per week ( OR =1.27, 1.20 ), reading and writing in the classroom during the break ( OR =1.27), reading in direct sunlight occasionally ( OR =1.20), using only desk lamp for writing at home ( OR =0.71), more than 1 hours of short-distance eye use for a break once ( OR =1.23) were associated with myopia among primary and secondary school students ( P <0.05). Conclusions Outdoor activities and short-distance use of eye among primary and middle school students in minority areas in Yunnan province are suboptimal. Enhancing the related environmental and behavioral factors can effectively mitigate the occurrence and progression of myopia.