The invention discloses a solar-energy-collecting-power-supply cable line fault intelligent on-line monitoring system which comprises a plurality of fault detectors, a concentration processor, a communication exchanger and a monitoring system server. A 2.4 G wireless communication module, a single chip microcomputer control unit, a current sensor and a lamp light warming module are arranged in each fault detector. The concentration processor is subjected to power supplying through a photovoltaic cell component and is connected with the monitoring system server through the communication exchanger. Sampling data of an ABC three-phase fault detector are received, fault information preliminary computation is carried out, data obtained after processing and analyzing are sent to the communication exchanger which decodes the fault information, and then the fault information is uploaded to a monitoring system server. The solar-energy-collecting-power-supply cable line fault intelligent on-line monitoring system can monitor fault situations such as short circuiting, grounding, overload, line breaking, power failure, three-phase unbalance and cutting theft in a comprehensive mode, and fault judging can be carried out quickly and accurately.