The microscopic features of small cell lung cancer are as follows: small cell carcinoma has small cells with little cytoplasm, round, oval or shuttle-shaped, resembling large lymphocytes or short shuttle-shaped, resembling oats, with dark-stained nuclei and less cytoplasm, also known as oat cell carcinoma. Small cell carcinoma is a malignant tumor derived from neuroendocrine cells. It is highly malignant, grows rapidly, metastasizes early and produces ectopic hormones, often involving the pleura and mediastinum, and often leads to superior vena cava syndrome. Most of the patients are middle-aged and elderly people, more than 80% of them are men and smoking has a close relationship with surgical resection treatment is relatively poor, but it is more sensitive to radiotherapy and chemotherapy. Therefore, it is recommended that patients must be detected and treated early, respect medical advice, develop good eating and living habits, and avoid adverse factors to prevent the occurrence of the disease.