The invention relates to an alternating current line fault ride-through control method for a unified power flow controller. The alternating current line fault ride-through control method comprises the steps of quitting a series side converter when a fault is detected; judging whether the fault is restorable line fault or not, if the fault is not the restorable line fault, stopping the operation of the unified power flow controller; if the fault is the restorable line fault, detecting whether the alternating current line returns to normal or not in real time; unlocking the series side converter after detecting that the alternating current line returns to normal; and disconnecting a series transformer secondary side bypass switch, and recovering the operation of the unified power flow controller. By adoption of the alternating current line fault ride-through control method, the fault point and the unified power flow controller apparatus can be isolated rapidly after the fault occurs; the unified power flow controller can be re-used rapidly after the line fault is removed and the line is returned to normal; therefore, the reliability of the overall system is improved; the safety of the unified power flow controller apparatus is ensured; and the usage rate of the unified power flow controller is increased.