The emergence of large-span bridge and extreme weather attract much more attention of researchers on the bridge buffeting problem. One of the most important factors that affect bridge buffeting response is wind velocity spectrum. In the precious investigations, wind velocity of various frequency has impact on the bridge buffeting response. While Proper Orthogonal Decomposition(POD)method is proposed to decompose the wind velocity to solve the above problem and a cable-stayed bridge was used to investigate the contribution of effective model to bridge buffeting response. The result showed that not all frequency ranges of wind velocity spectrum contributed to the response which had relationship with both structural self-vibration mode and turbulence effective mode coefficient.