The invention relates to a method for preparing high-polymer pulp and provides a preparation method for meeting the technical requirement of high-polymer pulp. The method for preparing high-polymer pulp comprises the steps of opening, preparing an assistant, stewing and the like and has the advantages of promoting moist expansion of celluloses, improving permeation of an alkali liquor into the celluloses rapidly, dissolving out non-cellulosic impurities such as pectin, wax and the like rapidly, and can also effectively protecting the cotton fiber carbohydrate, inhibiting peeling reaction, reducing degradation of celluloses, increasing the yield and the degree of polymerization of products, and effectively improving the strength of fibers.