AIM: To study the age distribution and refractive status of school age children with myopia and the correlation with ocular axis, corneal curvature and other biological parameters. METHODS: A total of 391 eyes of 196 school age children who were diagnosed as myopia were collected. Patients with other eye diseases causing vision loss were excluded. The patients were divided into three groups according to age and four groups according to diopter. All patients received visual acuity, intraocular pressure, slit lamp microscope, IOL master, optometry and fundus examination, and the results were recorded. Independent sample t-test, one-way ANOVA, LSD-t and linear regression were used to analyze the age distribution of diopter and its relationship with refractive parameters.RESULTS: There were 128(32.7%), 155(39.6%)and 108(27.6%)eyes in 6-8, 9-10 and 11-12 age groups. The average age was 9.29±1.64 years old. There were significant differences in SE(P<0.01)and AL(P<0.01)among different age groups. There were 134(34.3%), 162(41.4%), 74(18.9%)and 21(5.4%)eyes in SE ≤ -1.00D, -1.00D<SE≤ -2.00D, -2.00D<SE≤-3.00D and >-3.00D groups. The average SE was -1.54±0.89D. There was significant difference in AL among differences diopter groups(P<0.01). There was a linear relationship between SE and AL. The regression equation is (＾overY)=12.373-0.577X, R2=0.286, β=-0.577, P<0.001. And there was a linear relationship between astigmatism and corneal astigmatism. The regression equation is (＾overY)=0.084-0.502X, R2=0.389, β=-0.502, P<0.001.CONCLUSION: The age of the first onset of myopic ametropia in children is 9-10 years old, which is mainly low degree myopia. The growth of axial length is related to the increase of age and diopter and astigmatism is related to corneal astigmatism in children.