Abstract: The absorption of H2S in acid solution of Fe2(SO4)3 was carried out in order to study the technology of removing H2S by bacterial cultures of Thiobacillus ferrooxidans. Single factor test was designed to test the profile of desulfurization efficiency under different conditions of liquid–to–gas ratio (L/V), initial concentration of Fe3+([Fe3+]) and pH. Simulation analysis showed that the gas–liquid mass transfer rates in this experiment was much smaller than chemical reaction rate and was the controlling step of the H2S absorption process. The experiment results proved that liquid–to–gas ratio was the dominant factor of gas–liquid mass transfer rates, but initial [Fe3+] concentration and pH showed little effect. The optimal operation conditions were as follows L/V=0.6min－1；[Fe3+]=10 g·L－1; pH=2.0. Under such conditions, the efficiency of removing H2S by bacterial cultures was around 90%.