The invention discloses a fault automatic identification method and system based on an ant colony optimization algorithm. The fault automatic identification method comprises the following steps of: step 1, inputting a coherent attribute data volume, and setting an ant number and an iterative threshold; step 2, determining an ant moving direction according to the transition probability matrix; step 3, judging whether ants pass through all input data or not, if so, entering the step 4, and if not, returning to the step 2; step 4, judging whether the ant serial number is smaller than the ant number or not, if so, increasing the number of iterations and the ant serial number, returning to the step 2 until all ants pass through all input data, and entering the step 5; step 5, calculating a pheromone tau value; and step 6, judging whether the number of iterations reaches an iteration threshold, if so, outputting a fault profile, and if not, repeating the step 2-6 until the number of iterations reaches the iteration threshold. The coherent attribute data volume is tracked through the fault ant colony optimization algorithm, and a clear and continuous fault profile is obtained.