Molecular target therapy has become a new approach in the treatment of advanced non-small cell lung cancer (NSCLC). The sensitivity of lung cancer to epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) has been found to be associated with gene mutationss in the tyrosine kinase domain of RGFR. However, not all EGFR gene mutationss are sensitive to EGFR-TKIs. The review was conducted to study the research progress of EGFR mutations and the sensitivity to EGFR-TKIs and the mechanism of resistance of molecular target therapy in NSCLC.