Abstract: The aero-stability performance of Houlongxi Bridge in Taiwan is investigated via wind tunnel tests. The conditions for vortex induced vibration of concrete and steel deck sections, as well as the lock-in wind velocity regions and vibration amplitudes are obtained. The similarity and discrepancy between the wind-axis and body-axis for natural field and wind tunnel are expounded and discriminated. Then the aerostatic force coefficients are measured. The non-linear aerostatic response analysis is conducted finally. The research results reveal that the real bridge will not diverge when the velocity attains13.5m/s. In smooth flows, vertical bending and torsional vortex vibration occur for two models with +3° attack angle. For torsional vortex vibration，the wind velocity is quite high and lock-in region is wide. In flows with turbulence intensity of 10％, when attack angle varies form -3° to +3°, no apparent vortex can be observed The deck added attack angle incurred by static wind loads is very tiny. The wind load non-linearity plays negligible role on deck torsional and lateral displacement. Owing to the vertical lift wind loads will cause the obvious change of main cable rigidity, the vertical displacement is more relevant with the wind load non-linearity.