By conducting the study on 109 non-small cell lung cancer (NSCLC) patients at the Nghe An Oncology Hospital, we found that EGFR gene mutation is a cause of NSCLC. The average age of patients is 63.8 ± 10.6. 96.33% of all the patients have Adenocarcinoma. Using Scorpion ARMS technique for EGFR mutation identification, we found the rate of patients carrying the gene mutation was 40.37%. 55.96% of the patients are male (27.87% of those have gene mutation), 44.04% are female (56.25% of those have gene mutation). In all patients with gene mutations, 54.55% of patients carry LREA and L747-P753 delinsS mutation at exon 19. The rate of patients with the L858R gene mutation at exon 21 is 29.55%; the rate of double mutation at exon 19 and 20, 18 and 20, 18 and 21 is 9.09%. 15.91% of patients have targeted-drug-resistant gene mutation.