This paper presents the results of longitudinal study on ocular refractions during two years follow up period among 1004 senior high school and vocational school students. We performed the cycloplegic refraction with skiascope and auto refractor then measured the corneal curvature and axial length of each patient yearly. The results showed that during this period the average dioptor change was -0.5~-0.7D, keratometric change was insignificant, and the axial length average increased no more than 0.4mm. There was no difference between senior high school and vocational school students on refraction change We also found that the more myopic the greater dioptor changes.