The present invention discloses a power transmission line energy taking device which comprises at least two iron core coils for obtaining current from a power transmission line and at least two rectifier circuits which are correspondingly connected to the iron core coils one to one. The primary side of each of the iron core coils is connected to the power transmission line, and the secondary side of each of the iron core coils is connected to the input end of the rectification circuit. The output ends of the rectifier circuits are connected to the input end of a load. When the current in the power transmission line is in the preset range, the channel between the connected iron core coils and the load is switched on, and the connected iron core coils supply energy to the load. The corresponding preset ranges of the rectifier circuits are different, and the materials and numbers of turns of the iron core coils are different. According to the device, when the current in the power transmission line is in different ranges, the energy taking iron core coils are automatically switched by the rectifier circuits, and the effect of continuously supplying energy to the load is achieved.