The invention discloses a power transportation line-orientated mountain fire approaching risk estimation system which comprises a network interface module, a storage module and a processing module, wherein the processing module determines a power transmission line affected by an ignition point according to mountain fire happening information and power transmission line information, calculates risk indexes of mountain fire to all the power transmission lines affected by the ignition points according to real-time meteorological data in sequence, and finally judges the mountain fire prewarning risk level of the mountain fire event according to a mountain fire approaching risk index, determines mountain fire approaching risk prewarning information, and transmits the mountain fire approaching risk prewarning information to the network interface module for issuing. By integrated application of a satellite for monitoring the mountain fire and an automatic meteorological station for monitoring meteorological information and geographical information coordinate positioning information of the power transmission line in real time, the power transportation line-orientated mountain fire approaching risk estimation system can estimate the risk that the mountain fire approaches the line quickly after the mountain fire happens and issue a prewarning message according to an estimation result.