The invention discloses an open-communication-realization-based distributed feeder automatic decision-making method. A distributed FA mechanism is realized on a distribution terminal based on an open communication way; an IEC61850 open type communication system is fully utilized; and a topological connection model is generated dynamically and updating is carried out in real time. Under the circumstance that no distribution main station is needed, a fault point can be localized and isolated rapidly and precisely before outlet protection motion of the transformer substation, so that the power supply of the non-fault area can be recovered to the greatest extent. The method has advantages of low cost, great independence on a single control unit, and fast processing speed.