AIM:To observe ultra-thin-flap and thick-flap LASIK in treatment of low and moderate myopia before and after operation and to analyze the advantage or limitation in ultra-thin-flap LASIK.METHODS:A total of 154 cases of low and moderate myopia were chosen,81 cases(159 eyes) underwent the Moria 110 thick-flap LASIK in group 1,the other 73 cases(145 eyes) underwent the Moria 90 ultra-thin-flap LASIK in group 2.The actual corneal flap thickness and the corneal flap shape in the surgery,the complication between two groups before and after surgery,the cornea thickness,corneal flap thickness,surplus corneal stroma thickness,postoperative vision and intraocular pressure were observed.RESULTS:The actual corneal flap thickness of group 1 was 134.0±2.5μm;and that of group 2 was 93.5±5.9μm.There was significant difference between two groups (P< 0.05).There was no significant difference between two groups (P>0.05) in corneal flap shape,the complication,vision and intraocular pressure postoperative.There was fewer complication and thicker surplus corneal stroma thickness in group2 (P< 0.05).CONCLUSION:Ultra-thin-flap LASIK can produce the same good effect as the thick-flap LASIK.But the former can retain thicker corneal stroma bed,it can do wider diopter treatment with better security and wider adaptation scope,and will be the best choice for myopia people.