Background The aim of this study was to explore the clinical effect of the RGP contact lens in improving vision and controlling myopia progression of the unilateral high myopic children. Methods In this retrospective analysis case series study, we analyzed the clinical data for 23 subjects with unilateral high myopic children under 6 years old, with the spherical equivalent refractive error of the myopic eye from -5.0 D to -12.0 D, who were enrolled from the outpatient clinic at Beijing Tongren Hospital, China. Fourteen subjects could successfully fit the RGP contact lens, and nine subjects used the spectacle lens. Complete ocular examination was performed at the first visit at the clinic and every three months during the follow-up period. Results In the RGP group, the change of axial length (AL) of the high myopic eye was from 25.62 +/- 1.31 mm to 25.69 +/- 1.31 mm after 12 months. The change of spherical equivalent (SE) was from -8.73 +/- 2.54 D to -8.48 +/- 2.77 D. The best corrected visual acuity (BCVA) improved from 0.24 +/- 0.18 to 0.78 +/- 0.26. In the spectacle group, the change of AL was from 24.76 +/- 0.56 mm to 24.94 +/- 0.71 mm. The change of SE was from -6.16 +/- 2.86 D to -9.45 +/- 2.06 D. The improvement of BCVA was from 0.52 +/- 0.15 to 0.72 +/- 0.23. Conclusions Wearing RGP lens in the children with unilateral high myopia is a safe, convenient and effective method to improve the best corrected vision and controlling myopia progression.