Abstract: Non-small cell lung cancer (NSCLC) is the most important histological type of lung cancer. This disease affects a large number of patients, and the prognosis of advanced patients is poor. Although great progress has been achieved for existing treatment methods, challenges still exist. Cancer is a genetic disease, and its occurrence is accompanied by substantial genomic-sequence instability. (GT/CA)_n repeat sequence is a common microsatellite sequence serving as transcriptional function-related regions, DNA-methylation modification sites, and other functional sites. Its polymorphism is closely related to the expression of EGFR, HO-1, and HIF-1α in NSCLC patients. (GT/CA)_n repeat sequence is the breakthrough point to explore the molecular mechanism of NSCLC occurrence and development, develop molecular markers for diagnosis and prognosis and epigenetics research. This paper summarizes the studies on (GT/CA)_n repeat polymorphisms in NSCLC with the aim of providing references for relevant NSCLC research.