Abstract: Objective To study the strategy of sequential invasive-noninvasive mechanical ventilation in chronic obstructive pulmonary disease (COPD) specially explore the role of mechanical ventilation in patients with weaning difficulty. Method: Forty-five cases withe weaning difficulty during January 2009 ~December 2013 from Huludao central hospital emergency section guardianship room were recruited. Compare the rate of re-tracheal intubation rate and withdrawal machine success rate in two groups（intervention group, n=21, control group, n=24,）. Result: In the intervention group after weaning the 24h pH, PaCO2, significantly better than that of the control group (p <0.01),in the endotracheal intubation intervention group ，48h re-tracheal intubation rate was 9.5%, less than the control group ( 41.7%) (P<0.05), The intervention group relative risk of re-intubation was 0.147 (95%CI, 0.028~0.781). Intervention weaning success rate significantly higher than that of the control group (85.7% vs 50.0%,P<0.05) Conclusions Sequential invasive-noninvasive mechanical ventilation strategy helps reduce 48h intubation rate and improve the success rate of weaning.