The invention discloses a large current turn-off characteristic testing method. the method includes enabling connection of a to-be-tested device at an initial moment and increasing current gradually;applying turn-off signals at a first moment on the to-be-tested device and recording current as a first current value; detecting current change and enabling connection of a protection circuit which isin parallel connection with the to-be-tested device; if the current fluctuates or increases gradually, reducing the time interval between the first moment and the initial moment and performing testing again; if the current decreases, turning off the protection circuit after the current decreases to a specific level; enabling connection of the to-be-tested device again and applying turn-off signals, recording current as a second current value; detecting current change and enabling connection of the protection circuit; if current decreases continuously, increasing the time interval and performing testing again; if current fluctuates or increases continuously, determining the turn-off current maximal value between the first current value and the second current value. By adopting the testingmethod provided by the invention, damage to the to-be-tested device can be avoided and testing cost can be reduced.