Abstract: Absorbing moisture of electrode coating may easily lead to high diffusible hydrogen of weld metal, resulting in hydrogen embrittlement, blowhole, cold crack and other defects. Electrode was immersed to the petroleum ether solution containing stearic and Fe₃ O₄ powder, after that electrode was treated by the microwave oven and then became water-resistant. Microwave absorption material Fe₃ O₄ was used to reduce the diffusible hydrogen of weld bead, and promote the reaction of stearic acid and electrode surface. The results of FT-IR and SEM microscope indicate that Fe₃ O₄ absorbs microwave and melt stearic acid to form the water-resistant film. The diffusible hydrogen of the deposited metal of microwave treated electrode decreased to 70% of the one made by the untreated electrode, and such property does not vary very much as the the stoving time keeping 8 h.