On the base of the mathematical modeling of the process of electro-hydraulic sheet forging, a study was made of the influence of the pressure plate on the deformation of a rigidly clamped workpiece. The influence of the thickness of the pressure plate and its inner diameter, in relation to the diameter of the cavity of the cylindrical discharge chamber, on the energy of the plastic deformation of the workpiece and the shape of its deflection was studied. The significant influence of the parameters of the pressure plate on the pressure of hydrodynamic waves on the workpiece, the shape of its deflection and the efficiency of using the energy stored in the capacitor bank for plastic deformation of the workpiece were determined.