In this study, under the change of transmission of fairing, effect of behavior under wind induced is evaluated. Through Performing wind tunnel test, check the drag coefficient, vortex shedding, flutter, and performing CFD(Computational Fluid Dynamics), check the drag coefficient, flutter derivatives. At this time, the fairing maintains constant angle, length. And the transmission is realized from idealizing fairing part. The wind tunnel test carried out 3 cases about transmission 0%, 25%, 50% in fairing. In this test, we got drag coefficient according to attack angle and dynamic performance according to wind velocity each cases. CFD analysis carried out 3 cases about transmission 0%, 25%, 50% in fairing. In this analysis, we also got we got drag coefficient according to attack angle and flutter derivatives using moving mesh code according to wind velocity each cases. From extracted flutter derivatives, we found out flutter stability. Finally it is confirmed that the windproof efficiency of the bridge cross section is concerned about the transmission of fairing through compare test with CFD result.