The invention relates to a DC displacement type anti-voltage-loss device based on a T-shaped bridge structure. The device comprises: a power supply portion, a T-shaped bridge switching circuit, a voltage detecting circuit, a current detecting circuit, a driving circuit, a main control unit and a load; the power supply portion includes three power sources connected to an input end of the T-shaped bridge switching circuit, and a common output end of the T-shaped bridge switching unit is connected with the load; the current detecting circuit and the voltage detecting circuit are connected with aninput end of the main control unit; an input end of the driving circuit is connected to an output end of the main control unit; the main control unit inputs an instruction to the driving circuit according to the current of the load and/or the voltage of the power supply portion; and the T-shaped bridge switching circuit realizes conductive connection between at least one power source of the powersupply part and the load. The device can quickly switch to a standby DC power source to supply power when an AC power supply of a power grid loses voltage, and ensures the reliable contact of the ACcontactor. The device is small in size, is low in production cost, and has high practicability.