Abstract: Bioleaching of chalcopyrite with mesophile Thiobacillus ferrooxidans was performed at a low temperature (8～10℃). The results showed that the leaching rate of chalcopyrite for copper in sulfuric acid medium in 90 days was only 16.08%，the leaching rate in ferric sulfate medium was 21.3%，but for bioleaching it was as high as 37.96%. The optimal conditions for chalcopyrite bioleaching with Thiobacillus ferrooxidans were pH 2.0，10% inoculation，100 mesh ore size，2% slurry concentration. At the initial stage of the bioleaching process，adding 6g/L Fe2+ would greatly enhance bioleaching rate for copper to 53.51%.