In view of the dynamic design safety problem of large reversed tainter valve of high water head ship lock,self-vibration characteristics’3D FEM calculation about the valve and the system of the valve and boom is conducted to study the coupling effectiveness and sensitiveness of the main structure’s dimension.It reveals that the boom is dominant for the self-vibration characteristics of the system.The basic frequency of the system is 11.59 Hz and vibration mode is bending vibration of the boom itself.The self-vibration frequency of the valve and boom is slightly lower than that of the valve itself.The self-vibration characteristics of the system are affected obviously by the length of the boom and the thickness of the arm plate has little effectiveness.