The invention discloses a DC fault ride-through method for a power electronic transformer, and the power electronic transformer which is used for an AC-DC hybrid microgrid has two working modes: a voltage-stabilizing mode, i.e., a stabilizing a low-voltage side voltage; and a power mode, i.e., transmitting power to an AC power grid. When the power electronic transformer detects that the microgridhas a DC fault through the above two working modes, a DCDC device quickly locks a pulse, and calculates a to-be-provided short-circuit current according to a voltage drop value. An MMC device stabilizes an intermediate-stage bus voltage, and the DCDC device pulse is unlocked after the to-be-provided short-circuit current is calculated, a short-circuit support current is outputted till the bus voltage returns to a normal condition, and finally the working mode of the MMC device is switched to an operation mode before the fault, thereby completing the DC fault ride-through. The method can effectively improve the power supply quality of a microgrid system, and improves the stability of the microgrid system.