By using a specific inhibitor of anion transport, DIDS, the dependence on band 3 anion transport protein of superoxide anion radical (O(-)(2).) flux across red blood cell (RBC) membrane into RBC was studied and the effect of superoxide anion radical on anion transport in RBC membrane was also discussed based on the hemolytic t(1/2) in an isotonic solution of NH(4)Cl. The results showed that 40 &mgr;mol/L DIDS could completely inhibit anion transport by band 3 protein in RBC membrane, but had no effect on flux into RBC, proving that the O(-)(2). transport into RBC across RBC membrane was independent of band 3 protein the interaction of O(-)(2). with specific SH-group of membrane protein lowered the anion permeability, and it could be reversed by DTT and mercaptoethanol.