The introduction of targeted drugs for lung cancer has opened a new era of precision treatment for lung cancer, which has greatly improved patients’ survival time and quality of life. The efficiency of lung cancer patients with advanced EGFR mutations using targeted drugs can reach 70% to 80%, and the effective duration can reach 1 year, with an average survival of 2 to 3 years, and some patients’ survival even reaches more than 5 years. China Cancer Statistics 2015 shows that in 2015, there were 733,000 new cases (17.1% of the overall) and 610,000 deaths (21.1% of the overall) of lung cancer in China, making it the biggest threat of cancer or death due to cancer in China. In the United States, lung cancer targeted drugs have been developed to the second generation and even the third generation. 1.What does targeted therapy mean? The so-called targeted therapy is to inhibit the proliferation of tumor cells by targeting one or several targets in tumor cells with specific drugs. If we take war as an analogy, chemotherapy is an indiscriminate bombardment of human body cells, then targeted therapy is a laser-guided precise targeted bombardment of cancer cells. 2.Molecular targeted therapy has great advantages compared with traditional chemotherapy. Individualized treatment becomes possible, for example, the efficiency of EGFR-TKI treatment for non-small cell lung cancer with EGFR mutation is over 90%. Target specificity and mild toxic side effects. It is easy to administer orally, and the combined use with chemotherapy can improve the efficacy. 3.Appropriate population for targeted therapy? We have several systems to select the population of targeted drugs for lung cancer, one is based on the evidence of clinical studies as the indications of the target benefit population: the first is non-smokers, adenocarcinoma, especially alveolar cell carcinoma, from which the proportion of benefit is higher, and the efficiency of selection is also high; the second is EGFR gene testing. 4.What are the side effects of targeted drugs and related therapeutic measures? Most of the side effects of molecular targeted drugs are mild and do not need to be treated. Adverse events reported by more than 10% of the subjects were rash (44.0%), pruritus (15.7%) and diarrhea (11.3%). The overall incidence of rare interstitial lung disease and interstitial lung disease was approximately 0.28%. Generally mild to moderate adverse reactions, which the patient can tolerate, generally do not require special treatment. 5.Therapeutic measures after targeted drug resistance? Targeted drugs are increasingly used in the treatment of non-small cell lung cancer, but their gradual development of drug resistance is becoming a major clinical problem. Current studies suggest that multiple molecular mechanisms are involved in the development of drug resistance, and the exact mechanism of drug resistance needs to be further explored and studied. Patients can choose chemotherapy and other targeted drugs after drug resistance, depending on the patient’s condition and gene mutation.