The invention relates to a method for purifying arsenic-containing waste liquid by waste residues of silver extraction by cyanidation. Primary oxidation precipitation adsorption technology includes that the arsenic-containing waste liquid and arsenic-containing carbon gold concentrate are subjected to pulp conditioning in a mixing manner, pulp density is controlled to be 10-30%, hydrogen peroxide and charged oxygen serve as oxidizing agents, ferric sulfate is added to serve as a precipitating agent, pH (potential of hydrogen) of precipitates is controlled, stirring, pressure filtration and dehydration are performed to produce a filter cake and filtrate, and the filter cake serving as two-stage roasting raw ore enters a two-stage roasting acid-making process. Secondary deep purification curing technology includes that primary treated liquid and the waste residues of silver extraction by cyanidation are subjected to pulp conditioning in a mixing manner, pulp density is controlled to be 10-30%, high alkalinity and ferrous sulfate in the waste residues of silver extraction by cyanidation serve as precipitating agents, pH values are strictly controlled to be 6-7, oxygen is charged, stirring is performed for 2-4 hours, and pressure filtration and dehydration are performed to produce a filter cake and secondary treated liquid. Tertiary purified liquid is returned to a two-stage roasting pulp conditioning process and recycled, and a fourth stage includes that kaolin, calcium sulfate and cement are added into the used waste residues of silver extraction by cyanidation to produce balls, and curing and safety piling are performed.