Abstract:The contents, forms and available forms of thallium in tailings and soil samples from lead-zinc oxide-ore and lead-zinc sulfide-ore in Yunnan Province were analyzed, the migration and transformation process of thallium in lead-zinc tailings and its influencing factors were studied by acid production test and static leaching test. The results show that pH value and tailing composition are the main factors affecting thallium release, and the ratio of available thallium to total thallium in tailing is an important index to characterize thallium release risk, when pH = 2, the leaching rate of thallium in lead-zinc sulfide tailings reached 32.25% . The main way to cause thallium pollution in the soil around the reservoir is that thallium enters the soil from the water body in the tailings, a comprehensive thallium pollution control plan of "engineering measures + chemical precipitation + phytoremediation" was put forward.