The invention discloses a transformer electrical fault simulation device which comprises an oil container for accommodating insulating oil and an electrode pair arranged in the oil container and used for discharging electricity. A side wall of the oil container is provided with an oil taking hole for taking out the insulating oil, the oil container is provided with a first connecting hole positioned at the top and a second connecting hole located at the bottom, the electrode pair is connected with an oscilloscope and comprises an upper electrode and a lower electrode which are oppositely arranged, the upper electrode penetrates the first connecting hole, and the bottom of the lower electrode is connected with a ground electrode which penetrates the second connecting hole and is used for ground connection. After the insulating oil is added to the oil container, a discharging electric field is formed between the upper electrode and the lower electrode; after high voltage is formed after a power supply is connected, arc discharge is formed between the upper electrode and the lower electrode, so that the insulating oil in the electric field is ionized to generate gas and the gas is dissolved in the insulating oil; transformer electrical faults such as partial discharge and disruptive discharge can be simulated accurately through the oscilloscope, insulating oil samples under various electrical faults can be obtained continuously through the oil taking hole so as to measure the gas component content.