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The process of "dilute acid leaching-antioxidant + dilute acid leaching-initial delead from solid phase-acid leaching-removal of lead and arsenic from liquid phase-bismuth precipitation-dearsenication" was used for preparation of high-purity Bismuth Oxychloride from copper converter flue dusts.Firstly, dilute acid and manganese dioxide + dilute acid mixture were used as leaching agent, under the condition of 60 ℃ water bath, the liquid-solid ratio 2 ∶ 1, leaching 1 h respectively, so that most solubility element such as Cu, Zn, Sn could be separated and bismuth get enrichment.Secondly, use the configured solution which PH =4.5 at room temperature, the liquid-solid ratio 5∶1 primary delead from second Cu leaching residue, Thirdly, HCl-NaCl blend solution was used as leaching agent for second Cu leaching residue which has been dry, and the operation conditions of the acid leaching process were optimized.The results showed that acid leaching under the condition of the room temperature, 1mol · L-1 HCl, 2.5mol · L-1 NaCl, and the liquid-solid ratio 5 ∶ 1, was feasible, and the average extraction rate of bismuth reached 92 % , while the leaching solution concentration of bismuth was 0.20~ 0.30mol · L-1.By adjusting pH of leaching solution from 0.5 to 3.0 with the mass fraction of 1.66% Na2CO3 solution, over 98.20% of bismuth was selectively recovery as including bismuth precipitation and separated from element such as Cu, Pb, Zn etc, while the Bismuth Oxychloride purity was as high as 90% above.Deal with bismuth oxychloride by 2.0mol · L-1 NaOH solution, the purpose is to remove arsenic.After the comprehensive treatment, As in the bismuth oxychloride content from 3.80% to 0.03%, the arsenic removal rate reached 99.21%;Pb in bismuth oxychloride content from 3.46% to 0.189%, in addition to lead rate of 96.39%;Finally, Solution after Bi precipitation is treated with hydrochloric acid and sodium chloride mixed solution, and the solution is returned to leaching bismuth.