肺结核、肺癌是呼吸系统的常见病,咯血、哮喘是常见的内科急症,均为临床医师所熟知.但在临床实践中,由于疾病流行病学的变化(如肺癌患病率的显著增高,肺结核发病年龄向老年推移等),某些病例临床表现不典型,检测手段不完备,病史采集、体格检查不够详尽等,也可能误诊.本文仅对肺结核、肺癌、咯血,哮喘临床鉴别诊断略加讨论. Tuberculosis, lung cancer is a common respiratory disease, hemoptysis, asthma is a common medical emergency, are well known to clinicians.But in clinical practice, due to epidemiological changes in the disease (such as a significant increase in the prevalence of lung cancer, pulmonary tuberculosis Age of onset to the elderly, etc.), some cases of clinical manifestations of atypical, incomplete detection tools, medical history collection, physical examination is not exhaustive, may also be misdiagnosed .This article only for tuberculosis, lung cancer, hemoptysis, asthma clinical differential diagnosis slightly discussed .