The study on design and simulation of reduce vibration are carried out of the damp structure for the simulative experimental gear case to reduce vibration and noise of the ship gearbox. Multiple projects are designed for the gear case of the damp structure on the basis of the structure characteristic of the gearbox. The finite element analyze computation is carried out of box of gear case under the different project of the damp and the different damp material. The fine damp material and the optimization structure parameters of damp will be ascertained by the analysis of mode and frequency response. The contrastive analysis of vibration and noise is carried out for the box of fore-and-aft treat of damp structure. The analytical result indicates that the vibration and noise of gearbox will be reduced observably when the project of damp is adopted.