In order to see the direct joint effect of cooking oil fumes and hOGG1 Ser326Cys, which means to create a joint effect variable with 6 values according to exposure to cooking oil fumes (no/yes) and the SNP (Ser/Ser, Ser/Cys, Cys/Cys) and then compared to no exposure and ser/ser calculate ORs for the other 5 groups, we found that the ORs for the gene-environment interaction between Ser/Cys and Cys/Cys genotypes of hOGG1 codon 326 and cooking oil fumes for the risk of lung adenocarcinoma was 1.37 (95% CI: 0.77–2.44; P = 0.279) and 2.79 (95% CI: 1.50–5.18; P = 0.001), respectively. The gene discussed is OGG1; the disease is lung adenocarcinoma.