Biopsy is necessary for all diseases that need to clarify the nature of lesions. Biopsy can clarify the nature of the lesion, understand the development of the lesion, judge the therapeutic efficacy, and clarify the staging of the tumor, which is commonly used in the diagnosis of malignant tumors, such as lung cancer, gastric cancer and so on. For most of the diseases that are difficult to make differential diagnosis, pathological biopsy is the gold standard for clear diagnosis. Pathological biopsy is a method of local excision, clamping, puncture, scratching or cutting the lesion organ for histological examination, so as to make a clear diagnosis, and to clarify the nature of the lesion, to understand the development of the lesion, to judge the therapeutic effect and to clarify the staging of the tumor. It can clarify the nature of the lesion and provide different principles of treatment for different diseases, and at the same time, it can verify and observe the efficacy of drugs and provide a reference basis for the clinical use of drugs. The definitive diagnosis of the disease is a comprehensive judgment, patients need to carry out various tests before the definitive diagnosis, the results of pathological biopsy is the gold standard for definitive diagnosis, patients need to be actively examined, as early as possible early treatment. However, if the disease can be diagnosed through medical history, physical examination, routine laboratory tests, imaging and other tests, the pathology examination can not be done.