Abstract: In order to investigate the scour crater morphology and maximum scour crater depth of a large-diameter suction bucket foundation under different working conditions with wave-current coupling effects, and to compare and analyze them with typical working conditions under water flow and wave action, Flow-3D software is used to carry out a numerical simulation study on the scouring of a large-diameter suction bucket foundation, based on the typical hydrogeological data of a sea area project in Fujian Province. Combining theoretical analysis and numerical simulation, the scouring characteristics of the suction bucket foundation are systematically studied. Finally, based on the simplified model proposed by foreign scholars, a simplified model for scour pits that meets the safety requirements of practical engineering is proposed. The results show that: (1) the depth of the scouring pit of the suction bucket foundation is proportional to the water flow and wave height, the height of the exposed soil, the diameter of the bucket, and the size ratio; (2) in practical engineering, suction bucket foundations are used in the form of variable cross-sections, giving them a certain resistance to scour damage under wave action; (3) the scour depth and scour width of the suction bucket foundation caused by wave-current coupling are greater, and scour development is more rapid, with the maximum scour depth exceeding that under wave action or water flow alone, although the time required to reach scour equilibrium and stability is slightly longer than under water flow conditions; (4) there is a strong exponential function relationship between scour depth and time for suction bucket foundations under different working conditions with wave-current coupling effects. The research results can provide a reference and theoretical basis for practical engineering safety.