Abstract: Objective: To investigate the curative effect of sequential invasive-noninvasive mechanical ventilation on chronic obstructive pulmonary disease(COPD) combined with respiratory failure.Methods: Sixty-four cases of COPD with respiratory failure were randomly divided into two groups.On the basis of routine therapy,the patients in the control group were treated by the invasive mechanical ventilation and the treatment group by the sequential invasive-noninvasive mechanical ventilation.The arterial blood gas and the oxygenation index of the two groups were recorded before and after the therapy;the duration of mechanical ventilation,the length of hospitalization stay and the number of the cases receiving tracheotomy were compared.Results: The arterial oxygen pressure,the arterial carbon dioxide partial pressure and the oxygenation index of the two groups were significantly improved after treatment(P<0.05).After weaning,the total duration of mechanical ventilation and the length of hospital stay of the treatment group were much shorter than those of the control group(P<0.05);there was no statistical significance between the number of tracheotomy or mortality(P>0.05).Conclusions: Sequential invasive-noninvasive mechanical ventilation is an effective method for treatment of COPD combined with respiratory failure.It is worth popularizing.