The invention provides an ultrahigh-voltage AC equipment operation condition simulation system. The simulation system comprises an AC equipment branch under examination, a current generation branch and a voltage generation branch. The current generation branch is connected with the AC equipment branch under examination to form a closed loop circuit and used for providing test current for the AC equipment branch under examination. The voltage generation branch is connected with the AC equipment branch under examination and used for providing test voltage for the AC equipment branch under examination. A transformer bushing, a GIS current mutual inductor, an isolation switch, a basin-type insulator, a GIS bus and many other ultrahigh-voltage key equipment of the ultrahigh-voltage level can be simulated by the system. Working voltage and working current can be simultaneously applied to ultrahigh-voltage AC equipment, and operation wave, lightning wave, very fast transient overvoltage VFTO and other analog overvoltage can be applied to the ultrahigh-voltage AC equipment so as to simulate various operation conditions of the equipment in actual projects and research various performance of the equipment under the operation conditions.