At present, the incidence of lung cancer is increasing. In my clinical work, I found that many patients are diagnosed with lung cancer every week or every month. Lung cancer is divided into early, middle and late stages, and we clinically divide it into stage I, II, III and IV. The 5-year survival rate of stage I lung cancer patients can reach over 90% after surgery, while the 5-year survival rate of stage II lung cancer patients can reach about 60% after surgery, and the 5-year survival rate of stage IIIa lung cancer patients is only 30-40% after surgery. The current treatment modalities for lung cancer include surgery, chemotherapy, radiation therapy, Chinese medicine and molecular targeted therapy. Since lung cancer patients are often diagnosed at an advanced stage, chemotherapy is one of the main treatment tools, so chemotherapy and postoperative adjuvant chemotherapy are familiar to everyone. However, neoadjuvant chemotherapy, another chemotherapy treatment method, is not well known to everyone. Adjuvant chemotherapy is actually a perioperative treatment, not a new treatment, and has been introduced for more than a decade. However, preoperative neoadjuvant chemotherapy is still in the research stage, and more centers in China and abroad are doing research in this area. From the available evidence, effective preoperative neoadjuvant chemotherapy can improve the radicality of surgery by reducing the load of tumor cells. In addition, it can reduce the chance of intraoperative dissemination of metastases. Lung cancer is a systemic disease, and most lung cancer patients are already in distant dominant and non-dominant metastases at the time of consultation, even for those who can be treated surgically. Surgery and radiotherapy are local treatments that cannot treat micro-metastases that metastasize to distant sites through blood circulation or lymphatic system, while chemotherapy is a systemic treatment that can inhibit and kill cancer cells in both primary lesions and micro-metastases. Neoadjuvant chemotherapy has been widely used in recent years for preoperative chemotherapy of lung cancer, which can increase the chance of complete surgical resection and reduce the chance of intraoperative tumor spread, and preoperative tumor vasculature, which is not affected by the surgical procedure, allows more effective drug delivery and killing of microscopic lesions and metastatic lymph nodes, thus increasing the surgical resection rate, helping to reduce postoperative recurrence and metastasis, and thus improving patients’ postoperative survival rate and quality of life. Since the current postoperative adjuvant chemotherapy regimens are relatively blind, effective preoperative neoadjuvant chemotherapy can guide the postoperative adjuvant chemotherapy. Preoperative adjuvant chemotherapy and postoperative adjuvant chemotherapy are combined with each other, if the preoperative effect is good, the original regimen will continue to be applied after surgery; if the preoperative chemotherapy effect is not good, we should change the postoperative adjuvant chemotherapy regimen after surgery. In addition, stage IIIA or relatively late stage lung cancer, mainly squamous carcinoma, can benefit from preoperative neoadjuvant chemotherapy as the stage decreases from not being able to operate or difficult to operate to being able to operate. Pre-operative neoadjuvant chemotherapy controls the lesion on one hand, and also allows better treatment of previous heart disease, hypertension and diabetes. Effective preoperative neoadjuvant chemotherapy can also lead to more psychological improvement for the patient. Pre-operative neoadjuvant chemotherapy usually requires 2-3 cycles, and 3-4 weeks after chemotherapy before surgery. A small number of patients during this time may experience physical weakness or may be insensitive to neoadjuvant chemotherapy and have enlarged lesions, thus losing the opportunity for surgery, which is subject to further study.