Objective: To explore the application effect of noninvasive mechanical ventilation in chronic obstructive pulmonary disease(COPD) patients with respiratory failure. Methods: From April 2016 to October 2017, 150 COPD patients with respiratory failure in Ningbo Geriatric Rehabilitation Hospital were selected, and they were divided into observation group and control group by using the random number table method, with 75 cases in each group.The control group was treated with conventional comprehensive therapy, the observation group was treated with noninvasive mechanical ventilation method on the basis of the control group.The clinical effect of the two groups was compared. Results: In the observation group, the RR, HR and arterial blood PaCO₂ were significantly better than those in the control group(t=13.29, 12.48, 13.42, all P<0.05). The PaO₂, pH value in the observation group were significantly higher than those in the control group(t=5.91, 2.88, all P<0.05). The total effective rate of the observation group was 97.33%(73/75), which was higher than 73.33%(55/75) of the control group, the difference was statistically significant(χ²=1.81, P<0.05). Conclusion Application of noninvasive mechanical ventilation in COPD patients with respiratory failure can significantly improve respiratory function, and not only effectively shorten the treatment time, but also improve the treatment effect, and it is worthy of clinical promotion.