Abstract： Under the condition of actual sea state, the hydrodynamic characteristic of floating horizontal axis turbine is related to wave characteristics and floating carrier wave motion response. Slipping mesh is used in this study to analyze the hydrodynamic characteristic in uniform stream when the turbine is forced to produce roll and pitch coupling movement. Results show that the turbine axial load and energy utilization ratio fluctuates, and the calculation results in coupling motion and in pitching motion only are basically identical. The fluctuation amplitude of calculated rolling torque in coupling motion is bigger than that in rolling motion only. The difference of pitching torque between coupling motion and pitching motion only is highly dependent on the rolling frequency. Results of this study can provide reference for the study of motion response of floating carrier for floating tidal current turbine system. Structural design of turbine and control of the electric output.