Atmospheric and oceanic drag are the main environmental forces controlling sea ice drift. Oceanic drag includes the form drag generated by water pressure gradients on the side of ice lfoes or on ice ridges, and the skin friction generated by viscous lfow on the bottom of ice lfoes. In this study, we carried out a two-dimensional numerical simulation using FLUENT software to investigate the characteristics of dynamic lfow under ice with a smooth undersurface. We studied water drag and lfow ifeld distribution below the ice under different conditions of ice draft and lfow velocity, and the results agreed well with data from laboratory-based physical modeling tests, demonstrating the ability of the numerical model to reproduce the dynamic interactions between sea ice and the lfow ifeld. The degree of distortion in the lfow ifeld caused by ice increased as the ice draft increased. Vortexes occurred in the wake ifeld of the lfoe, and the centers of the vortexes moved away from the ice with increasing ice draft. The simulated drag of water on ice showed a clear linear relationship with the square of the lfow velocity.