Abstract: In order to explore the effects of microwave on oat seedling treatment and protein and nucleic acid metabolism of oat in seedlings stage under Na₂CO₃ stress, the influence of Bai Yan 7 oat seedling early metabolism and development under different power and time of microwave pretreatment using 2450 MHz is compared. The results show that low power (36%) pretreatment of Na₂CO₃ stress obviously promotes dry matter accumulation ,plant height and root length in single plant, which induce the NR and GS activity, suppress the activity of proteinase and RNase and increase the nucleic acid and protein accumulation. The pretreatment also reduces the free amino acid content in the leaves. Among them, 30 s treatment group is significantly better than the control group (p< 0.05); Medium power (58%), 15 seconds have positive regulation effect, but with the increase of the processing time visions inhibition emerged and enhanced. Under alkalic salt stress, through the regulation of nitrogen metabolism, microwave treatment promote the transformation of carbon from photosynthetic carbon metabolism to nitrogen metabolism , maintain the normal metabolism of nucleic acid and protein under salt stress and enhance the resisting ability of oat seedlings to Na₂CO₃ stress.