Abstract: Objective To investigate the status of myopia of children and adolescents in Sichuan Province, and to explore its related factors. Methods Schools in 168 districts （counties） in 21 cities （prefections） of Sichuan Province were selected as monitoring sites. At least 80 students from each school in each grade were selected for visual screening. Students in grade 4 and above of primary schools were required to conduct a questionnaire survey. The influencing factors of myopia were analyzed by Logistic regression analysis. Results A total of 286 472 children and adolescents were included in the study, with primary school students accounting for 44.99% and middle and high school students accounting for 48.69%. The incidence of myopia in children and adolescents was 51.42% （147 305/286 472）, and increased with the length of the grade. Girl （OR=1.329）, economically disadvantaged areas （OR=1.092）, senior grade （OR=2.168, 2.826）, seat change frequency ≥1/month （OR=1.297, 1.305, 1.319）, the average daily homework time in the past week ≥1 h （OR=1.106, 1.254, 1.346）, use of mobile electronic devices in the past week （OR=1.094）, frequent or occasional reading the electronic screen in direct sunlight （OR=1.184, 1.082）, frequent or occasionally reading a book or electronic screen lying down or on the stomach （OR=1.211, 1.107）, and both parents or one myopia （OR=2.375, 1.890） were risk factors for myopia in children and adolescents. Regional economy medium （OR=0.842）, the non‐Han nationality （OR=0.580）, frequency of adjusting the height of desks and chairs ≥1 time per year （OR=0.926, 0.936, 0.909）, daily eye exercises ≥2 times （OR=0.914, 0.857）, outdoor activities during recess （OR=0.755）, watching TV every day in the past week （OR=0.968, 0.906, 0.893, 0.827, 0.762） were protective factors for myopia in children and adolescents. Conclusions The incidence of myopia in children and adolescents in Sichuan Province is slightly lower than the national level but increases obviously with the increase of grade. It is necessary to strengthen myopia monitoring and intervention, especially in preschool children and girls.

Key words: Children, Adolescents, Myopia, Influence factors