For investigating the motion characteristic of the large semi-submersible barge in bad seas,the amplitude of motion response of semi-submersible barge was analyzed by numerical calculation in different operation.Based on the field construction work,the motion response of semi-submersible submergence was tested,and the hydrodynamic numerical analysis model and parameter setting were verified and improved.The proposed semi-submersible submergence construction work proposal can provide reference for the construction operation and safety control of the ship.