To the cataract patient after corneal refractive surgery, if the intraocular lens power was determined by conventional formulas, different refractive errors may be produced after intraocular lens implantation. This inaccuracy of the lens power mainly came from 2 aspects-errors of corneal refractive power measurement and errors of formulas. Besides, imprecise of ocular axial length measurement and invalid lens position calculation also contributed to the inaccuracy of lens power. Therefore, in order to reduce refractive errors of cataractous surgery in patient underwent refractive surgery, appropriate method should be used to estimate the refractive power of corneal, and proper formula should be selected to calculate intraocular lens power.