Rich silver-bearing low-grade complex sulfide ores can be found in great supply in China's Yunnan Province. The beneficiation experiment showed that it would be very difficult to separate Ag (Zn or Pb) minerals with traditional ore beneficiation methods. In the present work. acid pressure oxidative leaching of such complex sulfide ores in sulfate medium added sodium iodine and at the temperature ranging from 90 to 170 degrees C was studied to search for silver recovery alternatives. The Lab-scale experiments were conducted in a 2-L autoclave to investigate the influences of temperature, acidity, sodium iodide addition, oxygen pressure, oxygen flow rate on recovery of silver and zinc. The experimental results obtained show that under optimum conditions, recovery yield of silver and zinc reaches 71.5% and 41.29%, respectively. Crown Copyright (C) 2008 Published by Elsevier B.V. All rights reserved.