A series of coupled time domain simulations considering stochastic waves and wind based on five 1-h time-domain analyses are performed in normal operating conditions. Power performance and tower base Fore-Aft bending moment and pitching motion response of the floating spar-buoy wind turbine with 2 MW direct-drive PMSG have been analyzed by using HAWC2 that account for aero-hydro-servo-elastic time domain simulations. When the floating spar-buoy wind turbine is tilted in the wind direction, maximum of platform pitching motion is close to 4°. Statistical characteristics of tower base Fore-Aft bending moment of floating spar-buoy wind turbine are compared to that of land-based wind turbine. Maximum of tower base Fore-Aft bending moment of floating spar-buoy wind turbine and land-based wind is 94,448 kNm, 40,560 kNm respectively. This results is due to changes in blade pitch angle resulting from relative motion between wave and movement of the floating spar-buoy wind turbine.