Abstract： Objective:To analyze the case characteristics of Chronic obstructive pulmonary disease caused by occupational irritant chemicals (OI-COPD). To provide basis for revising its diagnostic criteria.Methods:From June to December 2021, we investigated the information of OI-COPD patients confirmed by Shandong Institute of Occupational Health and Prevention of Occupational Diseases, Guangxi Zhuang Autonomous Region Institute of Occupational Disease Prevention and Control, Qingdao Central Hospital affiliated to Qingdao University and other diagnostic institutions in the past five years, a total of 41 cases. The basic information of OI-COPD cases, occupational risk factors exposure information, medical history, smoking history and clinical symptoms were analyzed retrospectively. The measurement data were tested for normal distribution, which was described by ± s, and compared between groups by t test; Those who do not conform to the normal distribution are described by the median [ M ( Q1, Q3) ] and analyzed by nonparametric test; The counting data were expressed in frequency and rate (% ), and the comparison between groups was tested. Results:Of the 41 cases, 33 were male and 8 were female. The age of the patient diagnosed with OI-COPD was (49.5±10.3) years old, and the minimum age was 30 years old; Among them, 8 patients had a definite long-term smoking history (more than 5 years) ; The exposure duration of occupational risk factors was (18.6±10.3) years, of which 3 patients had exposure duration of less than 5 years; The occupational risk factors leading to OI-COPD include acids and acid-forming compounds, bases, aldehydes, nitrogen oxides, chlorine and its compounds, etc. The exposure level of occupational risk factors is related to the degree of COPD airflow restriction (χ 2=6.17, P <0.05). 18 patients with diagnosis age <50 years old were diagnosed as early-onset COPD. The incidence of respiratory symptoms in the early diagnosis COPD group was lower than that in the non-early diagnosis COPD group, and the FEV1% pred was significantly higher than that in the non-early diagnosis COPD group. The difference was statistically significant ( P<0.01 ) . Conclusion:The exposure level of occupational risk factors may be the risk factor affecting the degree of COPD airflow restriction. With the increase of the exposure level of COPD patients, the proportion of respiratory symptoms will also increase accordingly.