Windtunneltestsofaero-elasticmodeloftransmissiontowerwithscaleof1：40were conducted to investigate the wind effects on the transmission tower influenced by theaerodynamic damping under the conditions of terrain category Band typhoon wind field， andthe wind-induce acceleration responses of transmission tower without and with conductorswere obtained.The damping ratio was identified based on the EMD method， HHT transformand random decrement technique.The results induct that：the methods adopted in this papercan finely identify the structural dynamic characteristics； the aerodynamic damping increa-ses with the increase of windspeed under two conditions， and the same tendency can befound for the inflow turbulence； the structural modal frequency reduces for transmissionwith conductors， the aerodynamic damping and total damping increase.