Objective To investigate the effect of nikethamide combined with noninvasive ventilator in the treatment of chronic obstructive pulmonary disease ( COPD) complicated with respiratory failure.Methods 127 cases with COPD complicated with respiratory failure in our hospital from February 2014 to March 2016 were selected and randomly divided into observation group (72 cases) and control group (55 cases), the control group was treated with noninvasive ventilator therapy, and the observation group was treated with the therapy of nikethamide on the basis of the control group, the therapeutic effect, blood gas changes, etc of two groups were observed.Results The effective rate of the observation group was 80.56%, significantly higher than that of the control group (63.64%), the difference was statistically significant (P<0.05), the observation group after treatment 24h and 72 h pH and oxygen partial pressure (PaO2) were significantly higher than the control group, while the carbon dioxide partial pressure (PaCO2) was significantly lower than the control group, the difference was statistically significant (P<0.05), after treatment 24h and 72 h APACHE II scores in the observation group were (20.20 ±2.71) and (18.01 ±1.16), significantly lower than that of the control group, the difference was statistically significant (P<0.05), the hospitalization time, tracheal intubation rate and mortality rate of the observation group were (14.82 ±4.61) d, 11.11%and 4.17%, which were significantly less than those in the control group, the difference was statistically significant ( P <0.05 ) . Conclusion Noninvasive ventilator combined with nikethamide in the treatment of COPD combined with respiratory failure , can improve the effect of noninvasive ventilation, reduce the rate of tracheal intubation in patients.