Abstract：ObjectiveTo evaluate the efficacy and prognosis of CPAP\|PSV model and SIMV\|PSV\|PEEP model in the treatment of acute exacerbation of severe asthma Methods88 patients with acute exacerbation of asthma who were treated with mechanical ventilation were randomly divided into CPAP\|PSV mechanical ventilation group and SIMV\|PSV\|PEEP mechanical ventilation group The blood gas analysis,invasive ventilation time,live intensive care unit（RICU）time,ventilator\|associated pneumonia（VAP）incidence,weaning success rate and so on were observed in 30 minutes before and after weaning ResultsThe difference of blood gas analysis in two group was no significant,the ventilation parameters of CPAP\|PSV group were better than those of SIMV\|PSV\|PEEP group,and there were better effect,higher rate of off\|line and shorter living time of ICU with CPAP\|PSV model used machine on early stage Conclusion Mechanical ventilation should be used as soon as possible after reaching the machine in the patients with acute exacerbation of asthma,the effect of using machine is good and the rate of off\|line is high with CPAP\|PSV modeKey Words:Acute exacerbation of severe asthma；Mechanical ventilation；Positive pressure breathing；Intermittent positive pressure ventilation