The invention discloses a manufacturing method of cotton fabric based on light-induced polymer free radicals for degrading pollutants, which belongs to the technical field of functional textiles. According to the manufacturing method, an appropriate H donor agent and a crosslinking agent are selected by utilizing the characteristic that sulfonated polyether ether ketone has high activities to H atoms in organic substances under light induction, so as to cross-link and form a film on the cotton fabric rich in hydroxyl to prepare the self-cleaning fabric which can generate the polymer free radicals by lighting and has an elimination effect on the pollutants. The manufacturing method mainly comprises the following steps: (1) preparing a composite finishing liquid of light-induced free-radical polymer, wherein the finishing liquid contains the sulfonated polyether ether ketone, H donor polymer, the crosslinking agent, HCL (hydrogen chloride) and the like; and (2) padding and baking the cotton fabric in the finishing liquid. The cotton fabric which is prepared by using the preparation method and has a function of degrading the pollutants by the light induction has the effects of antibiosis, pesticide degradation, pigment degradation and the like, can be used for common clothing, medical fabric, household fabric and the like, and has a wide application prospect.