The invention discloses blending regeneration cotton yarn with the antimould effect. The cotton yarn is characterized by being manufactured by, by weight, 40-43 parts of waste cotton fabrics, 10-12 parts of cotton yarn leftover materials, 5-7 parts of bamboo charcoal fibers, 1-2 of Guran glycine, 0.5-0.7 part of cetyl trimethyl ammonium bromide, 3-4 parts of hydroxypropyl starch, 4-6 parts of hydroxyl silicone oil emulsion, 39-44 parts of polypropylene, 3-5 parts of nano-zinc oxide, 12-14 parts of liquid paraffin, 9-10 parts of nano-titanium dioxide, 1.5-2 parts of carboxymethyl cellulose, 1-2 parts of glyceryl stearate, 0.4-0.6 part of cason and a proper amount of water. The cotton yarn is formed by blending two kinds of fiber, is high in strength, good in toughness and resistant to wear, and makes up the shortcoming of pure-cotton fiber; by means of respective modification, the sunscreen effect is improved, the anti-microbial and antimould effects are good, the storage time is long, the process can be controlled conveniently in an industrial mode, and the product quality is high.