The offshore culture cage has been widely applied in the open sea recently. Floating collar is an important component for the fish cage structure, and the safety of floating collar is very important for the design of fish cage. The numerical model of floating collar was built by using the SHELL element based on the finite element method, the stress and deformation of the floating collar in current were simulated, and the numerical model were verified through the physical model experiments. The results showed that the numerical model could accurately simulate the deformation of the floating collar. Based on the numerical model of the floating collar, the stress and deformation of the floating collar under different water velocity were analyzed. The numerical simulation results indicated that the stress and deformation of floating collar were increased gradually with the increase of the velocity. The maximum deformation and stress of the floating collar in the floating condition was significantly larger than that for the floating collar in the submerge condition. In conclusion, the deformation and stress distribution of floating collar under high water current could be improved obviously when the floating collar was injected with water to make it be in submersible condition.