Objective To investigate the prognostic factors of severe chronic obstructive pulmonary disease ( COPD) in elderly patients, and to guide the clinical assessment and appropriate interventions. Methods A prospective cohort study was carried out from May 1993 to December 2010. A total of 178 elderly patients with severe COPD were recruited for baseline survey, and followed up for the living conditions, whether used non-invasive ventilation, and causes of death. A survival analysis was performed on all patients stratified by lung function. The significant factors on survival rate were analyzed. Results In this cohort the survival rates were 49% and 12% in five and ten years, respectively. The important factors for prognosis were age [ relative risk( RR) = 1. 043, 95% confidence intervals( 95% CI = 1. 010-1. 050] , forced expired volume in one second ( FEV1 , RR = 0. 019, 95% CI = 0. 007-0. 052) , FEV1% pred ( RR = 1. 045, 95% CI = 1. 012-1. 079) , lung function grade ( RR = 2. 542, 95% CI = 1. 310-4. 931) , body mass index ( BMI, RR= 0. 945, 95% CI = 0. 895-0. 952) , and pulmonary heart disease ( RR = 1. 872, 95% CI = 1. 188- 2. 959) . In severe COPD, non-invasive ventilation ( NIV, RR = 1. 167, 95% CI = 0. 041-1. 674) , pulmonary heart disease ( RR = 3. 805, 95% CI = 1. 336-10. 836) , FEV1 ( RR = 0. 081, 95% CI = 1. 001-1. 168) , and arterial partial of oxygen ( PaO2 , RR=0. 956, 95% CI =0. 920-0. 993) were the independent predictors.The patients using NIV had longer survival than those without NIV. The 5 and 10 years survival rate in the patients with NIV were 78% and 50% , much higher than those without ventilation which were 30% and 25% , respectively. In extremely severe COPD, FEV1 ( RR=1. 059, 95% CI =1. 015-1. 105) , arterial partial of carbon dioxide ( PaCO2 , RR=1. 037, 95% CI = 1. 001-1. 074) , age ( RR= 1. 054, 95% CI = 1. 013-1. 096) and pulmonary heart disease ( RR = 1. 892, 95% CI = 1. 125-3. 181) were the independent predictors. Conclusions Age, BMI, FEV1 , PaO2 , PaCO2 , pulmonary heart disease, and NIV were prognostic factors in elderly patients with severe COPD. The prognostic factors between severe and extremely severe COPD were not identical. Patients with severe COPD should be given early intervention, including progressive nutritional support, and long-term home oxygen therapy combining with NIV.