In the imaging process, the deformation of the plate caused by the structure of the drum, finally affecting the quality of the plate, we analyze and optimize the structure of the drum using the finite element method. Selecting the larger three factors affecting the plate deformation as the design variables, and taking minimizing the maximum deformation of the plate as the objective function, we establish the optimization model of the structure of the drum. We use the APDL parametrization language to create the geometric model and finite element model of the drum, and select the contact element to simulate the relationship between the plate and the surface of the drum, and use ANSYS software to optimize the optimization model. It is shown form the result that: the minimum of the maximum deformation of the drum getting from the 8th iteration is 0.0021535mm, significantly reduced compared with the initial value 0.002864mm. At this point, the internal diameter D2 of the drum is 300.04mm, the groove width L2 is 14.323mm, the external diameter of groove height D3 is 338.44mm. It indicates that that the smaller the internal diameter of the drum and the narrower the guide groove on the drum surface are, the smaller the maximum deformation of the plate is, and the guide groove height has little influence on the deformation. The results can be provided as theoretical reference for the design of CTP imaging drum, which has popularization and application value.