In order to prolong the in vivo half-life of Superoxide Dismutase (SOD) to improve the blood compatibility and to treat tissue injuries caused by activated oxygen during ischemia and hypoxia, erythrocytes were used as SOD carrier. The entrapment of SOD into rabbit erythrocytes was successfully employed. It demonstrated in vitro experiment that SOD activity maintained a stable level in the first 8 hours, and these erythrocytes can be stored at 4 degrees C for one week without loss of activity. The SOD carrier erythrocytes might be useful in clinical and special environmental medicine.