Abstract： Objective To investigate the expression and significance of super oxide dismutase activity and malondialdehyde concentration in the serum and adrenal grands of patients with adrenocortica diseases. Methods 12 patients with adrenal hyperplasia and 10 patients with adrenal adenoma which were carried out hospital surgery and confirmed by pathology, and 11 cases of normal as controls were selected.The serum level of Cu/Zn-SOD, Mn-SOD and MDA before operation, and Cu/Zn-SOD and Mn-SOD positive cells percentage of adrenal tissue were compared between three groups. Results Before adrenalectomy SOD activity was lower(P <0.05)and MDA concentration was higher in serum(P<0.05)than the control group.Cu/Zn-SOD positive cell was lower in adrenocortical adenoma tissue than that of adrenocorticohyperplasia and normal cortex(P <0.05).Mn-SOD positive cell had a significant difference among adrenocortical hyperplasia, adrenocortical adenoma and normal adrenal cortex tissue(P <0.05).Both SOD positive cell in adrenocortical adenoma tissue were the lowest of all.In addition,the expression of SOD in tissue had a significant positive correlation with serological expression in study group. Conclusion The superoxide dismutase activities and malondialdehyde concentration seemed to change with adrenocortica diseases.The detection of superoxide dismutase activities and malondialdehyde concentration in the serum and adrenal grands could be the potential methods for the diagnosis and differential diagnosis of adrenocortica diseases.