A numerical simulation study was carried out to study the coupling effect of the vessel, suspended load and mooring cables in the offshore operation of the crane vessel. According to the fundamental principle of dynamics, the potential flow theory, and the slender rod theory, the mooring system – crane vessel – suspended load coupling analysis program is established. The crane vessel "Lan Jing" is taken as the research object. The study focuses on the motion and dynamic behavior of crane vessel, loadings and mooring cable under the combined action of wind, wave and current environment. The research results validate the rationality of the multi-system coupling crane vessel computational model and obtain the relevant cognition of the motion response affected by environmental load, which can effectively guide the offshore lifting operations.