Laser shock forming of metal sheet is a novel technique by applying a compressive shock wave on the surface of the metal. It is a mechanical not a thermal process. In this paper, the deformation of TA2 sheet has been analyzed under single-time laser shock loading. By the theoretical analysis, a mathematical model of sheet deformation has been constituted, the relationship between the sheet deformation and the various parameters such as laser energy, sheet thickness and so on has been discussed. This model can be used to optimize the manufacturing parameters, to effectively control sheet forming and can provide theoretical basis for carrying out the large-scale laser shock forming of metal sheet. Considering some factors of affecting sheet forming, three experimental projects have been actualized in virtue of the high-power Nd∶glass laser shock device. Experimental results show that the theoretical deformation amount is comparatively approximate to the experimental results, so the correctness and validity of the theory used to calculate the theoretical sheet-deformation amount under single-time laser shock loading have been validated.