Abstract: To investigate the effect of mooring breakage on floating wind turbines（FOWT）,a multi-body dynamics model based on Spar platform is developed to study the effect of mooring breakage on the dynamic response of FOWT under operating conditions and misaligned wind and wave conditions,and the feasibility of two wind farm arrangements are discussed by considering the motion stability field before and after the breakage of mooring. The results show that:the surge and sway of FOWT is more affected by the mooring breakage,and the mooring lines located on both sides of the load direction have more influence on the wind turbine motion response after the breakage than the moorings at other locations;for the misaligned wind and wave conditions,the angle of wind and wave below 30° does not increase the adverse effect of the mooring breakage on the FOWT;for wind farms with shared anchors,the starshaped arrangement has the risk of collision with neighboring turbines,and it is appropriate to adopt the hexagonal arrangement with larger safety distance.