The invention relates to a short circuit fault self-adaptive judging method. The short circuit fault is judged by phase voltage and variation rate of the phase voltage. The judgment basis is formed through simultaneously meeting the three conditions as follows: the first condition: any one phase of voltage in the three phases of voltage suddenly drops; the second condition: the phase voltage dropping variation rate is greater than or equal to the variation rate threshold value; and the third condition: any one phase of voltage is lower than the short circuit fault judgment voltage threshold value. The electric system needs to maintain the balance of active power and reactive power in the whole system during the operation, when the unbalance of the active power and the reactive power occurs because some abnormal conditions occur during the operation, and the frequency or the voltage of the electric power system abnormally fluctuate and exceed the allowing range, the effective control measure needs to be adopted in time to avoid the further expansion of accidents. The method can be used for more sensitively judging the short circuit fault generated in the electric power system, the malfunction of a frequency and voltage emergency control device caused by the short circuit fault is avoided, and in addition, the method can be more preferably applicable to various types of short circuit faults of each voltage level electric network.