AIM:To observe the change of malondialdehyde (MDA) and superoxide dismutase(SOD) in serum and aqueous humor in the patients with diabetic cataract(DC),and explore the relationship between DC and oxidative stress.METHODS:The levels of MDA and SOD in serum and aqueous humor in subjects with (DC group,n=68),diabetes mellitus alone(D group,n=62),cataract alone(C group,n=60) and healthy subjects(NS group,n=50) were determined.RESULTS:The levels of MDA were increased,SOD were decreased in serum and aqueous humor in D group and C group than those in NS group(all P<0.05),but there was no significant difference between D group and C group;More significant changes of these parameters were in DC group than in D group or C group(all P<0.05).Pearson correlation analysis showed that MDA was negatively correlated to SOD(r=-0.835,P<0.05);Logistic regression analysis showed that:MDA and SOD were the impacting factors for DC(all P<0.05).CONCLUSION:The levels of MDA are increased,and those of SOD decreased in serum and aqueous humor in patients with diabetic cataract,the occurrence and development of DC may be related to oxidative stress.