The invention discloses a power communication network risk assessment method and system based on fault modeling, and the method comprises the steps: determining a to-be-assessed link in a power communication network, and obtaining a human factor, a natural factor, and an equipment factor, which are related to the to-be-assessed link, at a to-be-assessed moment; inputting the natural event into a natural factor fault model to obtain a natural factor fault probability; inputting the man-made event into a man-made factor fault model to obtain a man-made factor fault probability; inputting the equipment state parameters into an equipment factor fault model to obtain an equipment factor fault probability; calculating to obtain a risk assessment result of the link to be assessed through a presetrule According to the method and the system, through risk assessment of communication links and equipment nodes, risk values of a plurality of network nodes and links are sequenced, and fragile nodes, fragile links and a fragile area composed of the nodes and the links are determined, so that assessment of power communication network vulnerability is realized, and the method and the system can beused as a reference basis for network planning construction.