The invention discloses a processing method for chemical-preventing fabric, and belongs to the technical field of textile industry. The method is carried out on the basis of gray fabric woven from pure cotton yarns or polyester cotton yarns, and comprises the processes of blank inspection, seam overturning, singeing, cold batching, short steaming, washing and dyeing. The method is characterized by also comprising the steps of A, open-width washing, B, chemical-preventing arrangement, C, preshrinking treatment, and D, baking. The chemical-preventing fabric processed by the method has a function of preventing sulfuric acid, hydrochloric acid, nitric acid and caustic soda, has a good function of preventing chemical solvents such as o-xylene, methyl alcohol and acetone, and meets an EN14325 chemical-preventing standard.