Abstract: Purpose: To compare the consistency between the actual diameter of capsulotomy (ADC) and the predicted diameter of capsulotomy (PDC) in femtosecond laser cataract surgery（FLCS）, and analyze the factors that influence the deviation of the diameter of capsulotomy (DDC) between the actual and predicted. Setting: Aier Eye Hospital of Wuhan University, China Design: Retrospective observational case series Methods: The patients who underwent FLCS from March 2020 to March 2021 were reviewed. ADC in FLCS were measured and compared with PDC. The effects of age, gender and biometrics on DDC were analyzed. Results: 412 eyes of 336 patients were included. The mean age was 53.0±0.91(range 3 to 91 years). When PDC was set to 4.50mm, the results showed that ADC was 5.21±0.21mm with a significant difference between them (P0.05). No correlation (P>0.05) was found between both: DDC and the axial length (AL), DDC and the anterior chamber depth (ACD) as well as DDC and the average keratometry (Km); but a negative correlation was found between DDC and the lens thickness (LT) (r =-0.21; P<0.05) and DDC with age (r =-0.70; P<0.05). Using curvilinear regression analysis, a development of an age-depending correction formula was predicted : ADC=PDC+1.23-0.30ln (x) (x=age ≥3) (R² =0.65; F =752.39; P=0.00). Conclusions: The consistency of ACD and PCD were influenced by age and LT. For patients ≤40s, the younger the patient, the wider was DDC, for patients>40s, the DDC was small. The thicker the LT, the smaller the DDC.