AIM:To compare the distinctions of percentages of students with axial length/corneal radius ratio(AL/CR)>3 in different groups,and find out a key to monitoring for prevention and cure to myopia. METHODS:Totally 2970 students from the grade 1 and 4 of total primary schools,Yangfangdian district in Beijing had accepted examinations of distant visual acuity(DVA) by the standard logarithmic visual acuity chart and AL or CR by lOLMaster.The statistical analyses were performed using data for the right eye. RESULTS:Students of grade 1(n = 1282,mean age 6.44±0.52 years) and grade 4(n = 1688,mean age 9.25±0.46 years) were examined.Compared with grade 4,the grade 1 had shorter AL,better DVA and smaller AL/CR ratio(P= 0.000),but no significant difference in CR(P = 0.31).The male had longer AL,better DVA and larger AL/CR ratio and CR than the female.Percentage of students with AL/CR>3 in grade 4 were higher than that in grade 1(x~2 = 644.929,P = 0.000).Percentages of students with AL/CR>3 in older group were higher than those in younger group(x~2 = 644.807,P = 0.000).The worse the DVA,the higher the percentages of students with AL/CR>3 in two groups(x~2 =82.914,x~2 = 297.236;P = 0.000). CONCLUSION:Distance visual acuity and axial length growth are affected by the prolonging of age.With the age growing and visual acuity decreasing,the percentages of students with myopia risk factor would increase and myopia attack rate of groups would increase accordingly.lOLMaster has advantages in the ocular biometric parameters measurement for ophthalmology research.