AIM: To compare corneal flap thickness created with Ziemer LDV femtosecond laser and Moria M2 mechanical microkeratome. METHODS: A retrospective analysis of 100 cases (200 eyes) were performed with myopia and astigmatism (sphere -2.00- -12.00 diopters\[D\];cylinder 0.00- -3.50 diopters\[D\]). Fifty cases (100 eyes) were treated with Ziemer LDV femtosecond laser (Intended flap thickness was 110μm) and fifty cases (100 eyes) were treated with Moria M2 mechanical microkeratome using the 110μm head. Corneal flaps parameters were measured at center and 1mm,2mm,3mm from center located in meridian 0°,45°,90°,135°section, each section including seven points evaluated by RTVue FD-OCT one week after procedure. All measurement points were analyzed. RESULTS: The mean flap thickness at center was 108.69±11.75μm in Ziemer group and 130.75±13.36μm in Moria M2 group. There was a statistical difference in relative points between the two groups (t=24.791,P<0.01). The mean value of each section by subtraction a target flap thickness of 110μm was 9.70±6.84μm in Ziemer group and 21.63±11.79μm in Moria M2 group at center. Ziemer group was significantly less than Moria M2 group (t=17.493,P＜0.01). Flap thickness of seven points in the same section were significantly different in both Ziemer group and Moria M2 group（P<0.01）. CONCLUSION:Flap creation with Ziemer LDV femtosecond laser was superior to Moria M2 mechanical microkeratome in precision and predictability. The flap thickness of different point in the same section was not equal in two groups.