The invention provides a method for recycling high-pressure and low-pressure drain water in a steam engine workshop of a thermal power plant. The method comprises the steps of: connecting a drain water conduit with a pressure of 5.6 Mpa and a temperature of 300 DEG C of a high reduction main body to a steam supply pipe with a pressure of 0.65 Mpa and a temperature of 170 DEG C used by a oxygen extractor per se to fully recycle the drain water of high reduction main body; connecting a drain water of a low reduction main body and drain water of a temperature reducer to a two-level steam leakage pipe of a normally working steam turbine to fully recycle the drain water of the low reduction main body and the drain water of the temperature reducer; and connecting the drain water at the blind end of the low-pressure steam main pipe to the two-level steam leakage pipe of the normally working steam turbine, transmitting the drain water which serves as heating steam and fully recycling the drain water at the blind end of the low-pressure steam main pipe. According to the invention, by recycling the drain water of the high reduction main body and the low reduction main body, the drain water of the temperature reducer, the drain water at the blind end of the low-pressure steam main pipe, about 8.4 tons externally discharged steam can be saved per each hour. Through the implementation, the method for recycling high-pressure and low-pressure drain water in the steam engine workshop of the thermal power plant, disclosed by the invention, has the advantages of not only reducing the steam waste, saving the energy, reducing the consumption, lowering production cost, but also reducing environment noise and beautifying the environment.