Copper in the chlorination dust of copper-containing slag was recovered through the hydrochloric acid agitation leaching-N902 extraction process, and the main influential factors on the leaching of the chlorination dust were studied. The results show that under the conditions of 15% concentration of hydrochloric acid, ratio of liquid to solid 4 mL/g, reaction temperature 60℃ and reaction time 1 h, the leaching rate of copper is 98.95%. Meanwhile, the leaching rates of iron, nickel and zinc are 91.58%, 95.8% and 93.66%, but the leaching rate of lead is low at 5.96%. The leaching process realizes the separation of copper and lead effectively. N902 for copper extraction has good selectivity. When the mixing time, phase ratio, N902 concentration and pH value are 120 s, 1:1, 30% and 3.0 respectively, the copper concentration in the leaching solution decreases from 7.4 to 0.11 g/L, the extraction rate of copper is 98.51%, and the extraction rates of iron, nickel, zinc and lead are all lower than 1.5%.