The invention discloses a cotton leveling agent. The cotton leveling agent is prepared from the following raw materials in parts by weight: 10-25 parts of montmorillonoid, 1-4 parts of nano titanium dioxide, 2-6 parts of sodium aluminosilicate, 4-10 parts of glycerol, 16-30 parts of glycerol, 10-20 parts of sodium tetraborate, 6-12 parts of liquid caustic soda, 10-16 parts of sodium gluconate, 15-25 parts of sodium salt of polynaphthalene sulphonic acid, 2-4 parts of glacial acetic acid and 10-16 parts of deionized water. The cotton leveling agent does not contain prohibited substances such as alkylphenol polyoxyethylene ether and adsorbable organic halides, is easily dissolved into water, is resistant to acid and alkali, is resistant to hard water, is low in foaming, and is convenient to use. The cotton leveling agent is uniform in drying on cotton fabric, is good in uniform drying effect, is high in dry and wet friction firmness grade, hardly changes color while washed, does not stain, and is relatively high in washing-resistant firmness.