Abstract: autopsy cases of cbronic pulmonary heart disease in the elderly after mechan- cal ventilation were studied, and compared with another 30 cases without artificial ventilation。 The results showed that:（l） The first cause of death is pulmonary infection。（χ² test, P＜0.01）;（2） In the lung with respirator, the broadened alveolar septum, stenosed small airway. formationof hyaline membrane and microthrombus were more serious than the group without respirator.（P＜0.05 or 0.01）; （3） 5cases with respirator were observed with electron microscopy and foundproliferation of alveolar cells and foymation of hyaline membrane and; （4）The chest X-ray fiimswere reviewed in 2 cases with respirator and revealed more and more patch-like shadows sprea-ding all over the lung fields. The clinical significance and the pathogenic machanism were alsodiscussed in this paper.