Abstract: Objective To study the misdiagnosis reasons of lung cancer in young patients,and raise the awareness of the youth lung cancer and provide a reference for clinical diagnosis and treatment.Methods A retrospective analysis of clinical data of 48 patients younger than 40 years old who had been histologically confirmed as lung cancer and used to be misdiagnosed as tuberculosis initially by Shandong Chest Hospital from 2006 to 2012.Results Twenty-three cases were confirmed by fiberoptic bronchoscopy biopsy, 15 cases by CT-guided percutaneous needle biopsy, 5 by thoracoscopic biopsy, 2 by lymph node biopsy, 2 by pleural effusion cytology and 1 by sputum cytology.Conclusion Youth lung cancer is easily misdiagnosed as tuberculosis, and should be paid more attention. We should make the diagnosis in conjunction with the symptoms, imaging, fiberoptic bronchoscopy and percuta-neous needle biopsy, superficial lymph node biopsy.