Plate cylinder is the core component of the offset printing unit to complete the image transfer. The plate cylinder’s deformation will occur under pressure, resulting in the image’s deformation on the plate and the low printing quality. In this article, the three-dimensional digital model of plate, packing and cylinder are established by using solidworks software, they are assembled as a whole, the whole is imported into ANSYS finite element analysis software. The shaft of both sides of the cylinder are fixed, and the contact relations between plate, packing and cylinder body are defined, the pressure are load on the area with 5mm width on the surface of the plate cylinder. After solving, the flexural deformation of plate, packing and cylinder are obtained, through analyzing the axial and radial deformation of the plate, the graphic’s elongation which transferred from plate to blanket are received, consequently, an important basis of researching the image expansion will be provided.