The graphene samples with different numbers of layers are prepared by chemical vapor deposition, the relation between the number of graphene layers and the transmission at 550 nm is analyzed by graphene transmission spectrum. Besides, the damage characteristics of graphene under high intensity laser irradiation are analyzed. The results show that under the laser irradiation, for the single layer graphene, G band and 2D band shift toward high frequeney but for the multilayer graphene, only G band shifts a litile; the ratio between intensities of G band and 2D band in Raman spectrum characterizes the number of graphene layers, and it increases with the irradiated time, so the high intensity laser can peel the graphene.