Belonging to the new material field, the invention relates to a method for preparation of a super-water-absorbent material by hydrolysis of waste polyacrylonitrile fiber. The method is realized through the following way of: (1) dissolving waste polyacrylonitrile fiber with a solvent to obtain a uniform solution; (2) adding lye, mixing the substances uniformly, performing heating, and carrying out hydrolysis reaction; and (3) at the end of reaction, adding a precipitant to stratify the mixture so as to form a solid phase and a liquid phase, performing solid-liquid separation, and washing the solid, and carrying out drying and heat treatment, thus obtaining a super-water-absorbent material product. The method has the characteristics of high reaction rate, and short reaction time, which can be shortened from 7-8h to less than 1h. At the end of the reaction, the redundant alkali has no need for neutralization, thus avoiding waste of acid-alkali, and the separated solvent, alkali and precipitant can be recycled.