The invention relates to a method for improving the low-voltage ride-through capability of an air pre-heater, and the method comprises the steps: connecting a low-voltage ride-through optimization module between the air pre-heater and an actual voltage, wherein the low-voltage ride-through optimization module comprises an delta V which is used for judging a link, and the delta V module is connected with the actual voltage; constantly judging the difference delta V between a voltage of the air pre-heater and the actual voltage, wherein the air pre-heater is connected with a variable resistor through a delta V module and the variable resistor is directly superposed on the air pre-heater; changing the resistance of the variable resistor to adjust the voltage of the air pre-heater, wherein the air pre-heater is connected with a power voltage through the delta V module, and the power voltage is used for the voltage compensation of the air pre-heater. Moreover, the variable resistor has the upper and lower limits. On the basis that the voltage compensation is completed, the method reduces the voltage deviation in an adjustment process, improves the safety of a unit, and cannot cause the big fluctuation of parameters of the set.