Molecular targeted drugs have become the best choice for cancer treatment due to their significant efficacy, but unfortunately, all molecular targeted drugs have strict patient-specific applicability and only show therapeutic effect to those patients with clear targets in individual tumors. The selection of targeted drugs for lung cancer strictly depends on the detection and confirmation of molecular targets in patients’ tumor tissues, therefore, before doctors decide to use molecular targeted drugs for patients, patients need to go to standardized molecular pathology testing institutions to confirm whether there are corresponding molecular targets in their tumors. If there are targets, molecular targeted drugs are preferred; if there are no targets, other drugs or other treatment modalities are considered. A lot of scientific experiments and clinical studies have shown that the effect of targeted therapy for lung cancer patients is related to the mutation of epidermal growth factor receptor (EGFR) gene, so lung cancer patients should undergo EGFR gene mutation testing before receiving targeted therapy. EGFR stands for epidermal growth factor receptor, a membrane protein that plays an important role in the reproduction, growth, repair and survival of tumor cells. Numerous clinical trials have shown that EGFR and trospium are only effective in 30% to 40% of patients with non-small cell lung cancer. However, for patients with EGFR mutations, these two drugs are effective up to 90% of the time, while for patients with non-small cell lung cancer without mutations in the epidermal growth factor receptor gene, these two drugs have low or no therapeutic efficacy. Detecting whether EGFR gene mutation exists in non-small cell lung cancer patients can prospectively predict the effect of targeted therapy, provide good reference for doctors’ clinical use, and improve the accuracy and precision of targeted therapy. If patients have mutations, targeted therapy can be used decisively to bring positive treatment effect and hope for patients to live again. If the patient does not have the mutation, we can find other more suitable treatments for the patient, saving precious treatment time and avoiding unnecessary expenses.