The changing process of sheet velocity,displacement and thickness are investigated by means of numerical simulation. The displacement and thickness of sheet are measured through experiments after hollow laser shocks,which is compared with solid laser shock. The results show that velocity and displacement of sheet metal in loading area first occur and expand,which makes central sheet form rapidly and has a maximum displacement. Thickness thinning first occurs at the boundary of the loading area and then expands,which makes the sheet thickness in central and loading area decreases rapidly. Section profile of sheet metal is Gaussian curve approximately after hollow laser shocks. Reduction of sheet thickness in central area reaches the maximum,followed by the one in loading area. The deformation uniformity of sheet after hollow laser shocks is better than that under solid laser shock. This research has a great significance in promoting laser shock formability.