Abstract: In this paper we reported on the effects of BiPAP,a mask ventilator delivering at 2pressure level,in nine patients with COPD and one with acute respiatory failure（ARF）due tocardiogenic pulmonary edema,These nine patient were treated one hour a day for 7 days.ThePaO2 increased markedly as compared with the pretreatment PaO2.The pulmonary function tests,vc and FVC, also showed slight increase.One patient who sufferred from ARF with 3 episodesof cardiogenic pulmonary edema improved quickly symtomatically soon after being put on the ven-tilator three-four hours a day for 7 days.With the application of BiPAP,Another patient withOSAS also improved.This machine is a non-invasive,concenient and safe opparatus.It doesn’taffect the heart rate or blood pressure and its use opens up a new way in treating COPD andcardiogenic pulmonary edema.