Abstract: Through analysis of five typical cases, the author discribed the method for reasoning the relationship between trauma and lung infection. For lung abscess caused by trauma, evidence of body surface injury must first exist. Medical history and clinical data were also neccesary in the diagnosis.Lobal pneumonia is, by itself, an independent disease,trauma can only be predipitating factor for it. Traumatic pneumonia is the lung infection caused by chest or lung injury. In order to diagnose traumatic pneumonia, two points ware neccesary: 1. the evidence of chest injury; 2.trauma preceded the pneumonia.

Key words: trauma, lung infection, traumatic pneumonia