When wind load acts on the Power Transmission Line (PTL) with asymmetric cross section from icing and snowing, the generated vibration is termed ‘galloping phenomenon’. Since galloping phenomenon triggers short circuits or ground faults of the PTL, various galloping studies are being conducted, at home and abroad. However, galloping analysis is performed for single span in most cases, while actual PTL comprises multiple spans. In this study, PTL is modeled as a mass-springdamper system, using a multi-body dynamics analysis program, RecurDyn. To analyze dynamic analysis of the PTL, damping coefficient is derived, by using the free vibration experiment of the PTL and Rayleigh damping theory. Through flow analysis, the galloping occurrence condition was identified, and galloping simulation was performed, by modeling the wind load. The effect of galloping on the stress applied to the pylon, was analyzed by flexible modeling the pylon between spans. As a result, approximately 150% of stress is applied to the pylon, so the galloping phenomenon should be considered when designing the pylon.