The prevalence of chronic obstructive pulmonary disease (COPD) is rising in China, yet population-based evidence on COPD-related mortality risk remains limited. This study examined the association between prevalent COPD and all-cause and cause-specific mortality in a large Chinese cohort. 484,301 adults aged 30 to 79 years who received spirometry at the baseline of the China Kadoorie Biobank Study (2004-2008) were included. COPD was defined as FEV1/ FVC < 0.7. Mortality data were tracked via local death registries and national health insurance systems over a median follow-up period of 16.0 years. Cox proportional hazard models and competing risk regression were used to estimate hazard ratios (HRs) and subdistribution HRs (SHRs), respectively. The COPD group had higher all-cause and cause-specific mortality, with adjusted HR (95%CI) for all-cause mortality of 1.44 (1.41-1.47), and adjusted SHR (95%CI) of 1.09 (1.05-1.13), 1.06 (1.01-1.11), 3.30 (3.12-3.49), 1.45 (1.16-1.81), for circulatory disease, neoplasms, respiratory disease, and infectious disease mortality, respectively. Specifically, young COPD (aged < 50 years) showed a stronger mortality association than those aged ≥ 50 years. Moreover, individuals with preserved ratio impaired spirometry (PRISm) had a 1.4-fold higher risk of all-cause mortality compared with non-COPD participants. COPD is associated with a significantly elevated risk of mortality from all causes, circulatory disease, neoplasms, respiratory disease, and infectious disease in the Chinese population. Additionally, young COPD and those with PRISm faced significant mortality burdens.