Objective: Utilizing optical coherence tomography (OCT) facilitates the assessment of the gap between the peak of the base curve to the surface of the cornea, as well as examines the correlation between the thickness of the tear film and the fitting of the orthokeratology lens. Expected to provide an objective and quantitative evaluation method for the fitting of the orthokeratology lens. Method: Accumulated data on nearsighted individuals scheduled for orthokeratology treatment at our medical facility over the course of January through December 2023. Examination of patients who try on orthokeratology, Check items before try-on include naked vision,slitlamp, non-contact intraocular pressure, ocular fundus, eye position, corneal diameter, corneal topography, tear film rupture time, optometry, etc. Based on the examination re[通讯作者：郝静，主治医师，研究方向：斜视与小儿眼科 Email：jing2fly@126.com]sults, select standard films and try them on. Fluorescein staining shows the lens fitting state after patients adapt to wearing glasses. According to the performance of fluorescein staining, the inspected eyes are divided into three groups: lens fitting group, lens loose group, and lens tight group. Measure the tear film thickness of three groups of subjects using OCT and evaluate the differences between the three groups of data. Results: This study included a total of 49 myopic patients (77 eyes). The average spherical degree is (-3.09±1.26) D, the average cylinder degree is (-0.43±0.51) D, the average horizontal meridian power magnitude is (42.5±0.85) D, and Vertical meridian power magnitude is (43.26±0.99) D. Included 21 cases in the lens fitting group ( 34 eyes, 13 cases of both eyes, 8 cases of one eye) , 14 cases of lens loose group ( 22 eyes, 8 cases of both eyes, 6 cases of one eye), and 14 cases in the lens tight group( 21 eyes, 7 cases of both eyes, 7 cases of one eye). There was no statistical difference in the main basic data of the subjects in the three groups(all P>0.05). Use OCT to measure: Lens fitting group: the tear film thickness is 231.18±11.49μm. Lens loose group: the tear film thickness is 220.40±10.71μm. Lens tight group: the tear film thickness is 249.0±10.84μm. The difference between the three groups of values in the analysis of variance,P<0.0001,the results obtained are statistically significant. Conclusion: OCT can serve as a safe and reliable method for measuring the tear film thickness，which can help evaluate the suitability of orthokeratology and provide a non-invasive, more intuitive, and quantitative evaluation method for the fitting and evaluation of orthokeratology.