The utility model belongs to the technical field of energy supplying of high-voltage-side active electrical devices and particularly relates to an inductive energy taking device of a high-power power transmission line. In the device, a coil is wound on an iron core. The coil, an impact protective circuit, a high-frequency filtering circuit, a rectifier circuit, an energy release unit, an overvoltage protective circuit, a filter circuit, a voltage detection circuit, a voltage-stabilizing circuit, a super capacitor group, a reference source and a step-up control circuit are highly integrated on a printed circuit board and sequentially connected. Output ends of the rectifier circuit, the step-up control circuit and the reference source are connected respectively with the voltage detection circuit. An output end of the voltage detection circuit is connected with the energy release unit and the voltage-stabilizing circuit. Because an inductive power taking device is adopted, a power supplying scheme which is compact and simple and lower in cost is provided to a high-voltage line online monitoring device and the device has the advantages of being adaptive to different kinds of severe weathers, capable of all-weather stable and reliable power supplying and capable of long-term operation without maintenance and the like.