The invention discloses a weak-current signal transmission line for turn-to-turn insulation detection of a dry-type reactor. The weak-current signal transmission line comprises a transmission line bearing body, a lead is wound on the outer surface of the transmission line bearing body; the lead is periodically and repeatedly wound on the surface of the transmission line bearing body in a alternating and continuous mode of forward winding and reverse winding, and an insulation encapsulating layer is encapsulated on the outer surface of the wound transmission line. The transmission line greatlyreduces and mutually offsets the induced voltage of a strong electromagnetic environment, the electromagnetic interference noise of the environment cannot influence weak current signals of the thermistor wire and the thermocouple wire, and the inductance characteristic of the solenoid-type structure can effectively filter the interference of the alternating current and high frequency signals, so that the accuracy and the stability of signal transmission of the transmission line are further fundamentally ensured. The weak-current signal transmission line for turn-to-turn insulation detection ofthe dry-type reactor is suitable for the fields of online monitoring low-frequency (or direct current) and weak current signal transmission of power grids and power systems with high reliability requirements in complex electromagnetic environments.