Abstract: Mediastium lesion is a very common group of diseases in clinical work， such as thymoma， sarcoidosis，lymphoma， metastases of mediastinal lymph nodes， and so on.  The diagnosis of mediastium lesion is diffcult. The diagnosis of patients with mediastium lesions in recent decades has increasingly relied on minimally invasive tissue sampling techniques， such as endobronchial ultrasoundguided transbronchial needle aspiration， endoscopic ultrasoundguided fineneedle aspiration and mediastinoscopy.

Key words: mediastium lesion；bronchoscopy；mediastinoscopy；biopsy, needle