Objective To determine the prevalence and treatment of chronic obstructive pulmonary diseases (COPD) among citizens in Ningbo. Methods A multi-stage stratified random sampling was applied to select 8 neighborhoods and 3 villages out of 7 districts in Ningbo, people who were older than or equal to 40 years were enrolled as subjects. Information on the prevalence rate and treatment conditions of COPD was collected through respiratory symptoms and treatment questionnaire and lung function screening. Results A total of 5865 people were screened, 5674 of them met inclusion criteria and completed questionnaire and lung function test. Among whom, 3044 people were men (53.6%, the average age is 55.7±11.4), 2630 women (46.4%, the average age was 55.3 ± 10.7);473 of them were diagnosed with COPD, the overall prevalence rate was 8.3%, including 354 cases who had never been diagnosed as COPD, accounted for 74.8% of the total cases diagnosed with COPD, mainly in stage ⅠandⅡof the disease. There were statistically significant differences between diagnosed and undiagnosed patients in the overall COPD group and among different gender groups ( stagesⅠandⅡ) and (stagesⅢandⅣ). Among the 473 COPD cases, 119 (diagnostic yield 25.2%) of whom had been diagnosed with bronchitis, only 48 (41.2%of the diagnosed) received drug treatment, only 13 patients were treated regularly with medication. Conclusion The overall prevalence rate of COPD among those over 40 years of age in Ningbo was quite high and mainly had stagesⅠandⅡof the disease. The number of the diagnostic yield and those who received regular treatment are quite low. The current situation of diagnosis and treatment are far from satisfaction, management of COPD should be strengthened to reduce the burden for family and society.