Renewable resources industry is currently the fastest development of emerging industries of the whole world. In China, the huge market is waiting for development, since the renewable resources industry has been initially established. Lead recycling industry has rapid development along with a substantial increase of lead demand and shortage of lead ore resources. Lead waste has been fully utilized to reduce the lead pollution and waste of resources, which make lead into the virtuous cycle of "production, consumption and recycling". There are several pyro-metallurgy processes for lead recycling, which usually caused a variety of pollutants, such as lead dust, SO2, NOx, dioxin etc.. Flue gas containing SO2 in the process of secondary lead smelting must be treated in order to meet the emission standards and the recovery of sulphur resources. Several processes can be used, to treat the flue gas according to scale of secondary lead smelting, gas volume and SO2 concentration, including wet gas sulphuric acid process (sulphuric acid), sodium alkaline process (anhydrous sodium sulphite) and solvent process (liquid SO2). The principle, process characteristics and by-product utilization of each process is introduced respectively. Summaries and analysis of each process are made from several aspects, such as investment estimation, techno-economic indexes, operation and maintenance. Conclusions are made according to the different smelting conditions and finally the suitable gas treatment process is advised.