The invention discloses a remote-energy-supply high-voltage line current sensing detection system based on an optical fiber. The system comprises a current sensor, a current drive module, a light emitter, a photoelectric conversion module, a voltage regulator module, a remote host provided with an optical signal demodulation module and a large-power light source. The current sensor is connected with the current drive module; the current drive module is connected with the light emitter; the light emitter is connected with the optical signal demodulation module in the remote host through an optical signal transmission fiber; the large-power light source is connected with the photoelectric conversion module through an energy supply fiber; the photoelectric conversion module is connected with the voltage regulator module; and the voltage regulator module is connected with the current drive module. The system adopts the optical signals, so that transmission speed is fast, distortion rate is low, and the method is suitable for remote transmission; and a local sensing end is powered by a light source at the remote control end through the energy supply fiber, so that even if a high-voltage line at the local sensing end fails, normal operation of the local sensing end can still be ensured.