Abstract: The traditional buffeting response calculation of long-span bridge structures is based on the flutter and buffeting theory, which is conducted by means of sectional model pressure or force measurement test. At present, there is no report on the prediction of buffeting response of long-span bridges through sectional model vibration test. Based on the buffeting analysis theory, the two-wavenumber buffeting force considering the three-dimensional effect is derived. The prediction method of the long-span bridge buffeting response based on the sectional model vibration test is proposed based on the concept of integrated transfer function. Taking a suspension bridge with streamlined box girder as an example, the accuracy and feasibility of the prediction method are investigated through wind tunnel tests of a sectional model and a full-bridge aeroelastic model. The results show that the structural aspect ratio has a certain influence on the identification accuracy of the integrated transfer function. A larger aspect ratio leads to a higher identification accuracy of the integrated transfer function. Even if the turbulence integral scale is not much larger than the structure width, increasing the model aspect ratio can effectively reduce the influence of the three-dimensional effect. The method of identifying the integrated transfer function through the sectional model vibration test can be used to predict the buffeting response of long-span bridges with conservative prediction results.