Objective:To investigate the correlation between lung cancer and the polymorphism of xeroderma pigmentosum gene D(XPD) and X-ray repair cross complementing gene 1 (XRCC1) .Methods :The polymorphisms at loci XPD-751 and XRCC1-399 in 150 patients with lung cancer (lung cancer group) and 150 healthy volunteers (control group) were detected by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) .Results:There were significant differences in XPD-751 genotype frequency and mutant allele frequency between lung cancer group and control group (P= 0 .046 , P=0 .003) ,while XRCC1-399 loci had no significant difference(P=0 .395 ,P=0 .105) between the two groups .There were signif-icant differences in XPD-751 mutant allele frequency between patients with non-small cell lung cancer and patients with small cell lung cancer(P=0 .012) ,as well as among squamous cell carcinoma ,adenocarcinoma and other types of non-small cell lung cancer(P=0 .023) .When smoking and XPD-751 polymorphisms coexisted as risk factors ,the relative risk to lung cancer was 2 .812(95% CI:0 .956~6 .415) ,P=0 .336 .Conclusions :XPD-751 gene polymorphism was correlated with the occurrence of lung cancer ,especially with squamous cell lung carcinoma ,while XRCC1-399 gene polymorphism was not correlated with lung cancer .There is no interaction between smoking and the polymorphism of XPD-751 in lung cancer .