Lung cancer is still one of the common malignant tumors that seriously threaten human health, and the incidence rate is increasing at 3% per year. Among them, non-small cell lung cancer accounts for about 75%-85% of the total incidence of lung cancer, and 2/3 of the patients are already in advanced stage when they are diagnosed. With recent advances in research on histological subtypes of non-small cell lung cancer and drug efficacy and molecular biology, the 2011 NCCN guidelines have clearly suggested that treatment decisions for advanced non-small cell lung cancer should be based on histological subtypes. The WHO classification of lung cancer was revised in 2004, in which the histologic types of non-small cell lung cancer include: precancerous lesions, squamous cell carcinoma (squamous carcinoma), adenocarcinoma, large cell carcinoma, adenosquamous carcinoma, sarcomatoid carcinoma, carcinoid tumor, small salivary gland type of carcinoma and carcinoma that cannot be classified, among which squamous carcinoma and adenocarcinoma are the most common. A recent statistic shows that adenocarcinoma accounts for nearly 60% of lung cancers in men and more than 80% of lung cancers in women. This indicates that adenocarcinoma of the lung is currently the main pathological type of non-small cell lung cancer. I. Treatment strategy of advanced lung adenocarcinoma 1. First-line strategy: For patients with EGFR mutation, the use of small molecule tyrosine kinase inhibitor (gefitinib) should be given priority; for patients without EGFR mutation, platinum diphasic chemotherapy (pemetrexed, gemcitabine, paclitaxel, doxorubicin) should be given priority, and pemetrexed + cisplatin combined (or not) with bevacizumab should be considered as the treatment. 2. Second-line strategy: For patients who failed in first-line with gefitinib, second-line chemotherapy with platinum duplex (pemetrexed, gemcitabine, paclitaxel, doxorubicin) is the mainstay, with preference for pemetrexed + cisplatin combined (or not combined) with bevacizumab; for patients who failed in first-line combination chemotherapy, second-line treatment with gefitinib or erlotinib is preferred. The use of gefitinib or erlotinib in second line may not require mutation testing according to current guidelines. 3.Maintenance treatment strategy: for patients using gefitinib in first line, there is no maintenance treatment; for patients with effective first-line chemotherapy, maintenance treatment can choose pemetrexed or erlotinib, and maintenance treatment does not require mutation detection according to current guidelines, but maintenance treatment is limited to patients with good PS score. Treatment strategy for advanced squamous lung cancer 1.First-line strategy: the EGFR mutation rate is lower in squamous cancer patients than in adenocarcinoma patients, but for patients with positive mutation testing, gefitinib treatment is still available; for patients without mutation, platinum diphtherapy (gemcitabine, paclitaxel, doxorubicin) is preferred. 2.Second-line strategy: for patients who fail first-line gefitinib treatment, platinum diphasic chemotherapy (gemcitabine, paclitaxel, doxorubicin) is preferred; for patients who fail first-line chemotherapy, second-line treatment with single-agent doxorubicin or erlotinib can be chosen; second-line use of erlotinib does not require mutation testing according to current guidelines. 3, maintenance therapy: for patients who use gefitinib in the first line, there is no maintenance therapy; for patients who have effective chemotherapy in the first line, maintenance therapy can choose gemcitabine or doxorubicin or erlotinib; maintenance therapy does not require mutation detection according to the current guidelines, but maintenance therapy is also limited to patients with good PS scores. From the above treatment strategies, it seems that patients with advanced squamous lung cancer become refractory to treatment. Patients with squamous carcinoma have a low EGFR mutation rate, and the efficiency of targeted therapy is significantly lower than that of patients with adenocarcinoma; pemetrexed is significantly less efficient than other chemotherapeutic agents in the treatment of patients with squamous carcinoma; bevacizumab is also used only for patients with non-squamous carcinoma.