OBJECTIVE To explore the genotype characteristics of DNA repair enzyme XPD-751 and XRCC1-399 in the lens epithelium of cataract patients, and difference in free radical level. METHODS The genome DNA was extracted from respective lens epithelium of 30 cataract patients, their peripheral blood and 12 normal control's peripheral blood by using a Genomic DNA kit, and the polymorphisms of DNA repair enzymes XPD-751 and XRCC1-399 were examined by PCR-RFLP technique. Meanwhile, that of the cultured normal human lens epithelial SRA01/04 cells was carried out same way as reference control. Besides, the free radical level was detected by related kit. RESULTS The XRCC1-Gln399Gln or XPD-Lys751Lys genotype was found in the normal control group and cultured human SRA01/04 cells, while the polymorphism of XPD-Lys751Gln could be found in both lens epithelium and blood cells of the cataract patient group. However, there was no difference in XRCC1-399 phenotype between the patient and the normal control groups. There is difference in free radical level between the cataract (0.204 ± 0.07; 0.188 ± 0.07) and healthy subjects (t = 211.20, P < 0.05). CONCLUSION The polymorphism of XPD-Lys751Gln can be found in the lens epithelium of cataract patient group, suggesting that there may be association among the XPD-751 polymorphism with higher free radical level in the age-related cataract disease.