The invention discloses a manufacturing method for a fiber which can catalyze an oxidizing agent to quickly and efficiently oxidize and decompose a plurality of kinds of dye in the technical field of fiber manufacturing.The obtained fiber can be used for treating dye wastewater.The manufacturing method comprises the steps that firstly, a sediment polymerization method is adopted to synthesize polymer containing special functional groups; then, the fiber is spun through a wet-method spinning technology with a soluble alkali aqueous solution as solvent and an inorganic acid aqueous solution as a solidification medium; after washing and drying, in a soluble ferrite aqueous solution, complexation occurs among carboxylic acid groups, hydroxy and ferrous ions enriched in the fiber, the complex fiber is prepared, and the fiber has the character of catalyzing the oxidizing agent to oxidize and decompose dye.Compared with an existing powder or granular Fenton reaction catalyst, the obtained fiber has the advantages of being capable of being reused, high in treatment efficiency and dye removing rate, low in application cost and the like, and also has the advantages that non-woven or textile processing can be achieved, integrality is good, using is convenient, recycling is easy, and therefore the industrial practicality requirement can be met better.