Abstract: The SA and HPAM was used as compound carrier,and the PEG was added as pore-foaming agent to study the immobilized technology of acidithiobacillus ferrooxidans.Effect of concentration of the three materials on the mechanical strength of gelatinous microspheres and the activity of immobilized cells have been investigated.The optimal concentration of the three materials for SA-HPAM co-immobilization was obtained:mass fraction of SA solution 2.5%,mass fraction of HPAM solution 0.4%,volume fraction of PEG solution 2%.The rate of maximum oxidation was 2.853 g·(L·h)^-1 of the immobilized cells for Fe²⁺,and 98% of ferrous ions can be oxidized within 24 hours in that optimal condition.The oxidative activity of the immobilized cells still kept all right after the immobilized cells were reused for 15 times and refrigerated in the 3 ℃ refrigerator for two months.It show the good stability of SA-HPAM co-immobilized Acidithiobacillus ferrooxidans.