The invention, which relates to the field of optical fiber communication of the electric power system, discloses a non-blind-area online monitoring and automatic fault detection system for an opticalcable network of a power system, thereby solving problems that the fiber resources are wasted and the monitoring equipment cost is increased because the existing optical cable line standby fiber coremonitoring mode based on the board card type OTDR and only the trunk section of the optical cable line can be covered to cause blind spots of incoming and outgoing local optical cables and incoming and outgoing station optical cables of a transmitting terminal and a receiving terminal. The system comprises p monitoring groups including p monitoring units of local side monitoring equipment of an optical cable network local station and station side monitoring equipment of p transformer substations; online monitoring and automatic fault detection are carried out on the optical cable optical pathsof the P groups of power system optical cable networks; and in each group of optical cable optical paths, a receiving optical path and a transmitting optical path form a local station to carry out fiber communication with one transformer substation. According to the invention, a problem of low automation degree of the traditional optical power monitoring and manual fault detection is solved; thefault line detection time is shortened; the normal operation of an electric power optical cable network is ensured; and various monitoring requirements in the field are met.