AIM: To investigate the differences of myopia and ocular biological parameters of primary and middle school students in Urumqi.METHODS: A cross-sectional survey. A total of 2 495 primary and middle school students aged 7 to 18 from 4 schools in Urumqi were selected by judgemental sampling from September 2021 to November 2021 for relevant eye examination. The differences of ocular biological parameters and refractive status of students of different ages, genders and nationalities were compared, and the correlation between spherical equivalent(SE)and ocular biological parameters was analyzed.RESULTS: The detection rate of poor vision among the students was 80.36%, the detection rate of myopia was 55.91%, and the detection rate of astigmatism was 42.96%, among which the detection rate of low myopia was 63.80%, the detection rate of moderate myopia was 27.60%, and the detection rate of high myopia was 8.60%. There were significant differences in the detection rate of poor vision, myopia, astigmatism, SE and some ocular biological parameters among students of different ages and nationalities(all P<0.05). Among them, the detection rate of myopia, astigmatism and poor vision among Uygur and Kazakh ethnic groups was significantly lower than that of Han. The detection rate of poor vision and myopia among boys was lower than that among girls, while the detection rate of astigmatism was higher than that of girls. Spearman correlation analysis showed that axis length of eye, axial length to axial ratio, anterior chamber depth, and pupil diameter were negatively correlated with SE(rs=-0.664, -0.724, -0.320, -0.086, all P<0.001), and lens thickness was positively correlated with SE(rs=0.147, P<0.001).CONCLUSION: The prevalence of myopia among primary and secondary school students in Urumqi is high, and there are differences in the distribution of ocular biological parameters among children and adolescents of different ages and ethnicities.