Objective To investigate the clinical effect of long-term home non-invasive assisted ventilation in stable chronic obstructive pulmonary disease (COPD) combined with type Ⅱ respiratory failure.Methods Seventy-eight patients with stable COPD combined with type Ⅱ respiratory failure were divided into treatment group (26 cases) and control group (52 cases).Patients in control group were given conventional treatment,including inhaled salmeterol/fluticasone plus long-term home oxygen therapy (LTOT).Patients in treatment group on the basis of conventional treatment were given non-invasive assisted ventilation therapy for 6-8 hours a day,and the course was 12 months.Blood gas analysis index [pH,arterial blood carbon dioxide partial pressure (PaCO2),arterial blood oxygen partial pressure (PaO2)],pulmonary function index [forced expiratory volume in 1 second (FEV1),FEV1 percentage of expected value (FEV1％)],6 min walk test (6-MWT) distance,St George's respiratory questionnaire (SGRQ) and acute episodes.Results After 12 months'follow-up,there was no endotracheal intubation and dead patients in treatment group.Five patients had acute trachea intubation and invasive mechanical ventilation,and 1 case died in the control group.The index of pulmonary function (FEV1,FEV1％) in two groups after treatment was improved compared with that before treatment (P＜ 0.05).But FEV1 and FEV1％ over the same period in treatment group after treatment was higher than that in control group (P ＜ 0.05).The blood gas analysis indicators (pH,PaCO2,PaO2) in treatment group after treatment were improved compared with that before treatment (P ＜0.05).PaO2 in control group after treatment was improved,compared with that before treatment (P＜ 0.05),but there was no significant difference in control group in pH and PaCO2 levels before and after treatment (P ＞0.05).After treatment 6-MWT distance,and SGRQ scores were improved,compared with that before treatment (P ＜ 0.05),6-MWT from the same period in treatment group after treatment was higher than that in control group,and SGRQ scores was lower than that in control group during this period (P ＜ 0.05).There was significant difference in average acute episodes between treatment group and control group [(0.84 ± 0.16) times vs.(1.49 ± 0.78) times,t =-3.65,P ＜ 0.05].Conclusion Home non-invasive assisted ventilation treatment can improve blood gas analysis and pulmonary function in patients of COPD combined with type Ⅱ respiratory failure of stationary phase,increase exercise tolerance,improve the quality of life,and reduce the number of acute episodes and intubation rate.