Problem of lateral driving stability of the automobiles passing by the vicinity of pylons of cable-supported bridges in condition of strong cross wind exists obviously because of the alternative wind environment above the deck due to complex flow fluid around the pylon and the deck. Based on numerical wind tunnel technology, the numerical simulation investigation of alternating wind environment above the girder near A-shaped pylon for main span of the steel truss girder cable-stayed bridge of Zhengxin Yellow River Highway-railway Bridge is carried out, considering wind barrier set up on the deck or not. The result shows that the original program has significant effect on wind speed amplification and mutation near the pylon domain in cross wind. Further investigation on wind barrier set up on both sides of the girder section or near the A-shaped pylon along the bridge gives that wind barrier near the A-shaped pylon is useful for reducing wind speed above the leeward deck near the pylon and weakening its mutation. Deeply, taken a medium-size commercial bus as an example, lateral driving stability of the automobiles passing by the leeward lane near A-shaped pylon is discussed through the dynamic response simulation of the vehicle controlled by ideal-driver under cross wind. The results confirms again that the wind barrier near the A-shaped pylon is good for driving safety of vehicles passing by the leeward lanes in vicinity of A-shaped pylon. In all, above work provides technical support for the final implementation of the wind barrier as an engineering measure.