When the overhead transmission line is galloping, a variety of natural disasters occur on the role of the natural conditions, the vibration of conductor is one of the more serious harm to the power system. Over the past decade, as the construction of EHV and UHV, wire cross-section, tension, suspension height and span of overhead transmission lines are increasing, and hence the number of conductor vibration is significantly increased. Vibration in a large scale will led to frequent tripping or even broken line or tower collapses, which cause large area power failures and impact security and stability operation. Online monitoring method for overhead transmission line dancing is mostly needed to add additional equipment, however, once situated on the route environment overlying ice or high winds and other inclement weather, online monitoring is difficult to achieve. This paper presents a method, which is made correlation analysis based on the voltage and current acquired from both ends of the transmission lines, online monitoring of line galloping can be achieved.