Objective To investigate the accuracy and clinical significance of calculating the intraocular lens power using the online Haigis-L formula after refractive surgery. Methods 11 patients(16 eyes)with cataract who had corneal myopia refraction in our hospital were randomly divided into two groups. One group uses the Holladay-I formula built into Pentacam to calculate the power of intraocular lens, and the other uses the online Haigis-L formula. The accuracy of the prediction results of the two calculation formulas was then compared. Results There was no significant difference in the best corrected visual acuity between the 2 groups at 3 months after surgery. However, the uncorrected visual acuity of the online Haigis-L formula calculation group was better than that of the Pentaca embedded formula group, and the difference was statistically significant(P<0.05). It was found that the proportion of patients with online formula(Haigis-L)prediction error of 0～0.5 D, 0.5～1 D, and 1～2 D were 37.5%, 37.5%, and 25%, respectively. Pentacam embedded Holladay formula group prediction error between 0～0.5 D, 0.5～1 D, and 1～2 D patient proportion were 12.5%, 37.5%, and 50%. And there was a statistical difference between the two groups(P<0.05). Conclusion The online formula(Haigis-L)is more accurate than the Pentacam embedded Holladay-I formula for the calculation of intraocular lens power in patients undergoing LASIK refractive surgery.