Abstract: Objective To explore the relationship of acute exacerbation of chronic obstructive pulmonary disease (AECOPD) with environmental factors such as air quality and temperature. Methods From January 2004 to July 2009, hospitalized patients of AECOPD were collected from central hospitals.According to the result of pulmonary function test, the cases were divided into three groups:mild, moderate and severe ones.The analyses were made between the daily number of admitted patients in each group and the density of atmospheric pollutant and temperature which were measured on admission, and one day, three days, six days before admission respectively. Results On the whole, the daily number of admitted patients in severe COPD group showed positive correlation with API value of atmospheric pollutant irrespective of timing, and the same negative correlation with the maximum temperature or the lowest temperature.Moderate COPD group had positive correlation with the density of PM10 on d3, and showed the same negative correlation with the lowest temperature.Mild COPD group had positive correlation with the density API value of SO₂ on d0, and showed negative correlation with the lowest temperature. Conclusion Our study found that to some extent, the onset of AECOPD had correlation with air quality and temperature especially for patients whose pulmonary functions were severely impaired.This indicated that air quality and temperature were important factors for AECOPD.