A new fast equilibrium state method of highspeed train fluidstructure interaction was presented based on the vehicletrack coupling dynamics and aerodynamics. Firstly, the equilibrium state was calculated by the cosimulation method of fluidstructure interaction ignoring the track irregularity. Then, the static forces in equilibrium state were added to the traintrack coupling dynamics and the responses of highspeed train were calculated. With such method, the fluidstructure dynamics of a highspeed train were simulated under the case that the velocity of crosswind is 13.8m/s and the running speed of train is 350km/h. The train attitude, safety and comfortable indexes of train were compared with the equilibrium state method and cosimulation method. The differences of results between the equilibrium state method and cosimulation method are lower than 3.26%. It is shown that the calculation efficiency of equilibrium state method is higher than that of cosimulation method when calculating the highspeed train fluidstructure interaction in crosswinds.