METHODS: AECOPD-PRC plans to enroll 8100 hospitalized patients (≥ 18 years old with main diagnosis as AECOPD). Sample size estimation is based on estimated mortality of AECOPD hospitalized patients (∼5%). Study patients will be recruited from 108 hospitals across China, hospital selection follows the principle of stratification sampling (by provinces, municipalities, and special administration regions). Study patients will be recruited from Oct 2015, followed with a 3-year period visit. Ten visits are scheduled for each patient, including Visit 1 (within 3d after hospitalized), Visit 2 (the day discharged from hospital), Visit 3 to Visit 10 (1mo, 3mo, 6mo, 12mo, 18mo, 24mo, 30mo, 36mo after discharged, respectively). Over the period of hospital stay, information on demographic characteristics, clinical features, diagnoses (lung function, laboratory and imaging examinations, etc) and treatments will be collected. In the following visits, treatments and examinations, recurrence of AECOPD, re-admission to hospital, complications and mortality will be recorded. Additionally, several validated questionnaires will be applied at specific visits, including CAT, SGRQ and HADS. The primary study outcomes are all-cause mortality during hospital stay, AECOPD recurrence within 1mo after discharged. Secondary outcomes include all-cause and cause-specific mortality, frequency of AECOPD recurrence, lung function, life quality, health care costs in the 3-year study period, etc.