AIM:To investigate the operation effects of using 0.2g/L mytomycin C (MMC) on laser epithelium keratectomileusis (LASEK).METHODS:Two hundred and forty-nine patients (489 eyes) were devided into two groups:group MMC 128 patients 251 eyes;group 9g/L NaCl solution(NS) 121 with patients 238 eyes.0.2g/L MMC solution and 9g/L NS were intraoperatively applied to the cases respectively.The two kinds of instilled solutions were held up in the eyes for 30,60,90 and 110 seconds respectively according to the diopter ≤-3.00D,-3.25--6.00D,-6.25--9.00D,≥-9.25D.Observe indicate including the formation of corneal haze,the situation of visual acuity,the change of diopter,corneal endothelium density,the healing of cornea and so on.RESULTS:All the patients were followed up for 1 year.The clinical data of group MMC and group NS were respectively as follows:the occurrence rate of haze was 13.2% and 31.1%;the appearance rate of influenced visual acuity was 2.0% and 5.9%;the changes of diopter after 1 month,6 months and 1 year,MMC group was-0.67±0.11D,-0.58±0.21D,-0.54±0.18D;NS group was-0.87±0.14D,-1.30±0.26D,-1.05±0.20D;the corneal endothelium density of the two groups preoperation,1 month,6 months and 1 year after operation respectively was 3005.92±382.54 and 2991.99±323.18,2996.69±374.19 and 2970.11±317.79,2988.37±367.33 and 3080.21± 317.20,3000.05±299.84 and 2998.97±339.62.There was statistically significant difference (P<0.05)in those index.But there were two cases 2 eyes of filamentary keratitis after taking off lense in group MMC.CONCLUSION:Using MMC 0.2g/L solution intraoperatively can effectively inhibit haze formation and therefore improve the results of LASEK greatly.