The hydrometallurgical process route of "alkaline conversion-acidic lead extraction-sulfuric acid lead separation" was studied for the separation and enrichment of lead from copper smelting slag. The principle of efficient transformation of lead in slag was mainly explored, and the effects of various factors in each process on the transformation, leaching and precipitation of lead were investigated. The optimal experimental conditions for each process were determined. The results show that by adding NaOH, the higher free alkalinity will cause PbSO₄ in the slag to enter the liquid phase in the form of plumbous acid, increasing lead loss and reducing recovery rate. In the acidic extraction stage, the reaction time and free acidity have a significant impact on the leaching rate. Under the conditions of free alkalinity of 15 g/L, liquid volume to solid mass ratio of 5/1, and temperature of 30 ℃, the alkaline transformation reaction is carried out for 3 h. Then, under the conditions of free acidity of 20 g/L, liquid volume to solid mass ratio of 5/1, and atemperature of 30 ℃, the slag are leached with nitric acid for 2 h. Finally, lead is precipitated with sulfuric acid under the conditions of a sulfuric acid coefficient of 0.8 to 1.0 and temperature of 30 ℃. The conversion rate and leaching rate of Pb in the slag can both reach over 95%. The process can efficiently separate and enrich lead from copper smelting slag, and the effect is good.