In this paper, selecting a WM wind turbine as research object, the model of coupled rigid and flexible multibody dynamics was built and topology graph of wind turbine was designed. Through the interface force element the cosimulation between whole unit analysis model and the software AeroDyn and controller was completed. From the modal analysis, first six step natural frequency and modal shape of wind turbine was obtained and it can be concluded that resonance between wind turbine and key speed interval exciting frequency would not occur. The displacement dynamic response, acceleration dynamic response and blade tip deflection in three coordinate directions of tower in the upwind direction were obtained and it can be concluded that extreme gust makes the tower structure displacement increases suddenly and the twinkling fluctuation occurs sharply. Additionally, the maximum blade tip deflection appears in the x direction and it may make the blade collide with tower which would influence the operation safety of wind turbine.