The influence of operational variables in the Sulfonated Chemi-mechanical pulp (SCMP) of cotton stalk was studied, and the hydrogen peroxide bleaching sequence was carried out. The major factors, such as sulfite sodium charge (calculated as Na2SO3 3%, 6%, 9%or 12%on oven-dry cotton stalk), active alkali charge (calculated as NaOH 2%, 4%, 6%or 8%on oven-dry cotton stalk) and the maximum temperature (110°C, 130°C or 150°C) was investigated. The result shows that: the pulp physical property was influenced significantly by sulfite sodium and active alkali charge, at an increasing tendency with above factors. The optimal chemical treatment cooking conditions could be proposed as follows: sulfite sodium charge 9%, active alkali charge 2%, maximum temperature 130°C and liquor ratio 4:1. What’s more, the single H2O2 bleaching sequence was employed, which can provide pulps with brightness 58.0%ISO.