Abstract: The aerodynamic lift forces, lateral forces and rolling moment on high-speed power cars were investigated experimentally to study the effects of crosswinds on the aerodynamics of EMU (electricmultiple unit). The dynamics of curve negotiation ofhigh-speed power carunder crosswinds was analyzed using software SIMPACK. The results indicate thatwheel load reduction induced by crosswind is an importantsafety factor. Underdiscussed conditions, the safe speed ofpower car is less than 220 km/h under a mild wind (15 m/s); and there is no safe speed under a gust crosswind (25 m/s) when power cars run at speed of100 ~ 180 km/h.