The utility model discloses a distributing type ice coating online monitoring system based on long distance, install on the high -voltage overhead circuit by OPGW, brillouin optical time domain reflectometer, raman fiber amplifier and industrial computer, OPGW including the system to the transformer substation is connected with two places, brillouin optical time domain reflectometer passes through OPGW and is connected with raman fiber amplifier, the industrial computer passes through USB line and net twine and links to each other with brillouin optical time domain reflectometer, solves present transmission line distributing type ice coating online monitoring system monitoring wire way scope generally about 30KM, nevertheless reaches kilometers up to a hundred in transmission line icing region a bit in the sichuan mountain area, and the system can't satisfy the problem of the monitoring of the long transmission line icing distribution that the icing region is greater than 30KM at present.