Wind tunnel tests and analyses of the response of the concrete pylon for the Seo Han Grand Bridge were conducted using aeroelastic model technique. A 1/250 scale aeroelastic model was used to measure the responses of the pylon at the several critical locations and to find any possible vibrational behavior. In order to confirm the model design and fabrication, natural frequencies and mode shapes measured from the model were compared with those from the calculation. Tests were conducted under the various angles ranging from $0^{circ}$ to $90^{circ}$ to find the critical angle of the wind. In order to evaluate the sensitivity of the response to changes in structural damping, a series of tests were conducted with two different values of structural damping such as 0.2% and 1.0% of critical. Additional tests were also conducted considering construction sequence.