Abstract: Experiments of Knelson gravity separation-tailings cyanide leaching and all -slime cyanidation leaching were carried out in Phatem gold ore. Economic analysis on the cost of the mine construction and production of the two kinds of process were made. The research shows that compared with all-slime cyanidation leaching process, mine construction investment of the reelect-tailings cyanide leaching process will increase 1.766 3 million yuan, but recovery rate of the gold will only increase 0.17 %. Value added of net profit is -781,100 yuan. So, allslime cyanidation leaching process is recommended. Study shows that only when the gold recovery rate can increase more than 1 % , adding Knelson gravity separation process before allslime cyanidation leaching process will be economic feasible.