AIM: To investigate the bacterial flora and antibiotic susceptibility testing of conjunctival sac in adolescents after wearing orthokeratology(OK)lens.METHODS:A total of 101 adolescents aged 8 to 14 who admitted to outpatient department of Xi'an No.1 Hospital from September 2021 to August 2022 were recruited in this cross-sectional observational study. There were 51 cases wearing OK Lens(wearing group)and 50 patients not wearing contact lens(non-lens group), the right eye of all patients was selected into the group. The culture of bacterial flora in conjunctival sac between the two groups were compared, the species were identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, and the antibiotic susceptibility testing was carried out for the positive strains cultured in the wearing group.RESULTS:The positive rate of conjunctival sac bacterial cultured in the wearing group and the non-lens group was 68.6%(35/51)and 60.0%(30/50), respectively(P>0.05). In both groups, the bacteria with the highest detection rate were staphylococcus epidermidis and staphylococcus aureus. The sensitivity rates of the strains detected in the wearing group to drugs are as follows: Levofloxacin(98%), Moxifloxacin(98%), Gatifloxacin(98%), Cefuroxime(98%), Cefathiamidine(98%), Rifampicin(98%), Chloramphenicol(96%), Cefoxitin(95%), Clindamycin(80%), Gentamicin(74%), Fusidic acid(72%), Tobramycin(64%), Compound sulfamethoxazole(26%), Mezlocillin(10%), Azithromycin(6%), of which the sensitivity rate of Gram-positive cocci was 100% sensitive to Vancomycin.CONCLUSION:Gram-positive cocci are the main bacteria isolated from conjunctival sac of adolescents after wearing OK Lens. Wearing OK Lens will not significantly increase the positive rate of conjunctival sac bacterial flora. Results of antibiotic susceptibility testing may provide guidance for empirical medication in patients wearing OK lens after eye infection.