The bioleaching effect of different concentrations of silver ion catalysis on chalcopyrite tailings has been investigated in shaking flasks. In this paper, A.t ferrooxidans were selected for conducting the bioleaching process. Experiments were carried out under the condition of pulp density 150 g/L, inoculation amount 106~7 cells/mL, pH around 2.0, culture temperature 30°C, rotation speed 150 r/min. The silver ion concentrations varied from 0 to 0.05g/L. After a bioleaching time of 24 days, 82% and 55% of copper was dissolved from the ore for the silver ion concentration of 0.01 g/L and 0.001 g/L respectively, compared with only 37% and 13% recovery for the silver ion concentration of 0 and 0.05 g/L. Preliminary tests showed that the silver ion concentration had a markedly catalytic effect on the copper extraction. The experimental results also showed that high silver ion concentration would inhibit the copper extraction. That was because the silver ions at high concentrations are toxic and they can suppress the bacteria growth and oxidation activity.