Abstract: In order to solve the problem of ship energy efficiency optimization effect that is difficult to be verified on real ships,it is necessary to carry out the research on three-dimensional（3D） dynamic simulation and virtual-reality fusion verification method of ship energy efficiency.Based on the idea of digital twin simulation modeling,a ship 3D model,a multi-temporal virtual scene,and a data-driven ship energy efficiency optimization model are constructed,and twin data mapping and virtual-reality interaction control methods are studied.Combined with the real ship and complex sea state data,a ship energy efficiency 3D dynamic simulation system is designed,and a virtual-reality fusion verification method for ship energy efficiency optimization based on digital twin is proposed.The analysis results of a case study show that the proposed method can verify that the fuel consumption of a ship can be reduced by about 2.2% under the same sailing environment and operation scenario conditions.The designed 3D dynamic simulation system for ship energy efficiency can reproduce the navigation scene and operation state of the ship,and the verification analysis of the effectiveness of the ship energy efficiency optimization model and algorithm can be realized by adopting the virtual-reality fusion verification method and fiction.