Objective To investigate the influence of ocular residual astigmatism (ORA) on the correction of astigmatism by FS-LASIK with vector analysis.Methods The records of 182 patients who had accept FS-LASIK between January,2016 and April,2016 were retrosepectively reviewed.The patients whose ORA ≥ refractive cylinder were assigned to high ocular residual astigmatism group (HORA group),ORA ＜ refractive cylinder were assigned to low ocular residual astigmatism group (LORA group).All of the patients were followed 6 months or more.The visual acuity,error ratio and correction ratio were compared between HORA group and LORA group.Results The preoperative ORA of all patients was (0.61 ± 0.27) D,in which ＞ 0.75 D were 58 cases (31.9％),and the HORA group was more than the LORA group (P ＜ 0.05).At postoperative 6 months,there was no statistically significant difference in vision acuity between the HORA group (1.06 ± 0.15) and LORA group (1.08 ± 0.15) (t =0.97,P =0.35).There was statistically significant difference in the error ratio between the HORA group (58.11 ± 63.23) ％ and LORA group (26.12 ± 35.37) ％ (t =3.43,P ＜ 0.05).There was statistically significant difference in the correction ratio between the HORA group (146.45 ± 86.63) ％ and LORA group (122.56 ± 36.31) ％ (t =2.81,P ＜ 0.05).Conclusion The error ratio and correction ratio of astigmatic correction by FSLASIK is significantly higher in eyes with high ORA than in eyes with low ORA.Vector analysis should been carried out before the FS-LASIK.