In order to solve the problem of poor vibration absorption effect of multi-modal coupling vibration in the study of dynamic vibration absorption of offshore platform, the design method of Dynamic Vibration Absorber (DVA) for suppressing the vibration of platform plate structure is studied. Taken thin plate as the specific research object, the mathematical model of thin plate and DVA is established, the selection of mass ratio of DVA is analyzed, the optimal installation position of DVA in discrete mode and dense mode is discussed, and the optimal design formulae of damping ratio and frequency ratio of DVA are given. Based on the above research, the dynamic vibration absorption method of plate structure on platform is summarized. Taken a cabin simulation model as the application object, the vibration control of the five modes involved in bulkhead vibration is carried out, and the maximum vibration reduction effect is 92.2%. After the modification and design of the DVA, the vibration reduction effect of the first and fifth modes is improved by 0.9 percentage points and 6.1 percentage points, respectively. The above results verify the effectiveness of the dynamic vibration absorption method of platform structure, which is of certain guiding significance for vibration protection of offshore platforms.