The invention discloses a preparation method of a nano EGCG protein rod. The preparation method comprises the following steps of: S1, preparing nano EGCG: S11, obtaining casein sodium salt from milk,adding purified water and dissolving to obtain a 5% casein sodium salt solution; S12, adding tea polyphenol powder into the 5% casein sodium salt solution while stirring to obtain a mixed solution of0.5% tea polyphenol and 5% casein sodium salt; S13, carrying out ultrasonic treatment on the mixed solution of 0.5% tea polyphenol and 5% casein sodium salt for 5 minutes to obtain nano tea polyphenoldispersion liquid; S14, refrigerating and drying the nano tea polyphenol dispersion liquid to obtain the nano EGCG; and S2, preparing the nano EGCG protein rod. According to the preparation method disclosed by the invention, the used casein sodium salt, purified water, tea polyphenol powder, nano tea polyphenol, additives, milk mineral salt, nano EGCG, green tea powder, skimmed milk powder, protein raw materials, crushed nuts, resistant dextrin liquid, protein rod and the like are all non-toxic and do not damage human health.