The dual coupling investigations of wheel-rail and pantograph-catenary are very necessary for HSRS to promote rationally the construction velocity to 400 km/h. The rigid-flex coupling simulation analyses indicate that the instability hunting oscillations of high-speed bogies have effects to both lateral accelerations at the middle floor of lightweight-designed carbody and the pantograph base on the carbody roof. And for the more than 300 km/h operations of DSA380 pantograph, the cracks at both top pipe ends of upper arm are caused by the two sensitive factors of fluid-solid coupling effect and the clearance shocking interaction, instead of the pressure on the carbon contact strips, by which the correctness of dual coupling model is validated sufficiently. The acceptable solution to high cycle fatigue can be reached finally for the improved structures of high-speed pantographs through the exact analyses of the local higher stress and their sensitive influencing factors.