OBJECTIVE： To investigate the correlation of XRCC1 rs25487 polymorphism with the occurrence of lung cancer. METHODS： A total of 208 patients with primary lung cancer of Han nationality in Northern Jiangsu selected from the Affiliated Hospital of Xuzhou Medical University during Sept. 2015-Jul. 2016 were included in lung cancer group. A total of 214 healthy volunteers of the hospital underwent physical examination were included in control group. PCR-RFLP was used to detect the genotypes at XRCC1 rs25487 locus， and Logistic regression model was used to evaluate the correlation of genotypes with the occurrence of lung cancer. RESULTS： There was no statistical significance in the distribution of age and gender between 2 groups （P＞0.05）. The proportion of smoker in lung cancer group was significantly higher than control group， with statistical significance （P＜0.05）. AA， AG and GG genotypes were detected at rs25487 locus of XRCC1 gene. The frequency of AA， AG and GG genotype were 43.5％， 41.1％ and 15.4％ in control group and 28.8％， 48.6％ and 22.6％ in lung cancer group， respectively. The frequencies of genotypes in 2 groups were in line with Hardy-Weinberg equilibrium （P＞0.05）， but there was statistical significance in genotype distribution between 2 groups（P＜0.05）. Compared with AA genotype， the risk of lung cancer in individuals carrying AG genotype increased by 2.265 fold [OR＝2.265， 95％CI（1.299， 3.950），P＝0.040； after corrected with gender， age and smoking history OR＝2.309，95％CI（1.274，4.185），P＝0.006]， with statistical significance. The risk of lung cancer in individuals carrying GG genotype increased by 1.310 fold [OR＝1.310，95％CI（0.771，2.228），P＝0.318；after corrected OR＝1.429，95％CI（0.811，2.518），P＝0.217]， without statistical significance. CONCLUSIONS：rs25487 locus mutant heterozy- gosity of XRCC1 gene is risk factor of lung cancer in Han nationality from Northern Jiangsu， and smoking can increase the risk of lung cancer.