The invention relates to a non-ferrous metal smelting high-arsenic contaminated acid arsenic fixing process which sequentially includes the steps: pre-neutralization, to be specific, mixing iron-containing slag or iron-containing reagents and smelting contaminated acid, controlling Fe/As molar mole ratio, throwing mixed slurry and the contaminated acid into a pre-neutralization tank, performing reaction, controlling the pH (potential of hydrogen) value of solution, thickening pre-neutralization slag slurry to obtain bottom flow, supernate and gypsum slag, and using the gypsum slag as a cementretarder for sales; oxidation, to be specific, supplementing iron sulfate serving as an iron source reagent as required, heating the pre-neutralized supernate, adding hydrogen peroxide serving as an oxidizing agent for oxidation, controlling oxidation-reduction potential, and completely oxidizing trivalent arsenic into pentavalent arsenic; crystal form iron arsenate precipitation arsenic fixing, to be specific, controlling reaction temperature, adding seed crystals, controlling reaction endpoint pH values by adding lime milk, and conveying bottom flow subjected to two-stage arsenic precipitating reaction to a landfill through filter-pressed crystal form iron arsenate solids. The arsenic fixing process has the advantages of simple process, low cost, good treatment effects, low environmentalpollution risk and the like and is applicable to non-ferrous metal metallurgy industries.