The invention discloses a sizing process of superfine denier yarn nylon fabric yarns. The sizing process comprises the following steps of (1) sequentially adding 1 to 2 weight parts of lenzing viscose, 2.1 weight parts of formaldehyde, 1.3 weight parts of hydrolyzed polyacrylonitrile, 1.4 weight parts of hydroxy propyl methyl cellulose and 14 weight parts of phosphate starch into 35 weight parts of de-ionized water; performing uniform stirring; (2) then sequentially adding 2.2 weight parts of sucrose fatty acid ester, 1.8 weight parts of alkylphenol ethoxylates, 1.3 weight parts of dinonyl decyl barium sulfate and 2.1 weight parts of mannan; continuously performing stirring until the sufficient and uniform mixing to obtain slurry; (3) soaking the yarns into slurry for sizing; pressing away residue liquid; performing drying. After the sizing, the yarns have the advantages that the hair is fit; the strength is obviously improved; the wear-resistant performance is good; the yarn stretching performance is good.