Objective To study the cause, treatment and prevention of the appearance of corneal endothelium edema (CEE) after LASEK to treat myopia. Methods LASEK was performed to treat myopia on 1911 patients (3814 eyes) with an age range of 18～45 years, average (25.4±6.7)years. Preoperative sphere was between -0.75 and -14.00 D and the cylinder was 0 to -5.50 D. Corrected visual acuity was better than 1.0. Large facula plane formula scan or Small facula flying-spot scan was used for the LASEK incision. After surgery, measurements were recorded for near and distant vision, best corrected visual acuity, slit lamp slave microscope examination, non-contact intraocular pressure, subjective and objective optometric tests and corneal topography at two weeks, one month, three months, six months and one year. CEE cases were identified, graded according to the time period and analyzed for further study to correlate the cause and method of treatment. Results After surgery, CCE appeared in varying degrees in 75 eyes (1.97%). Patient age ranged from 25 to 42 years, average (32.7±7.8)years. CEE occurred in every follow-up period but gradually declined with the use of more recent technology and renewed equipment available for treatment. The trends remain unchanged. The CEE cases were graded as follows one day after surgery: level 1, 56 eyes; level 2, 17 eyes; and level 3, 2 eyes. Intensive corticosteroid therapy was used for treatment plus treatment to prevent infection in the short term. CEE disappeared with treatment: there were 56 eyes at 3 days, 18 eyes at 1 week, and 2 eyes at 2 weeks. Visual acuity slowly recovered within a month and the change in vision tended to stabilize by six months. CEE occurred in each group and increased with the severity of myopia. CEE had a lower incidence in the mild and moderate groups compared to the high and very high groups. But statistical analysis with SPSS 10.0 software showed no significant difference between the groups (P>0.05). Conclusion The appearance of CEE is caused by multiple factors aft