Inclusion Criteria:
* During the screening visit (Visit 1), the age range is 40 to 80 years (including the threshold value), and gender is not restricted;
* The subjects with chronic obstructive pulmonary disease (COPD) as per the GOLD 2025 diagnostic criteria, and the symptoms before screening were consistent with COPD for at least 1 year \[GOLD 2025 standard: the subjects have chronic respiratory symptoms such as shortness of breath, chronic cough or expectoration, and/or have a history of exposure to risk factors, and the pulmonary function test results show: the forced expiratory volume in one second (FEV1) after using bronchodilators / forced vital capacity (FVC) \<0.7\];
* During the screening visit (Visit 1):· FEV1/FVC after using bronchodilators is \<0.7;· 30% of the expected value ≤ FEV1 after using bronchodilators \< 80% of the expected value;
* COPD stable within 4 weeks prior to screening period (Visit 1);
* During the screening period and treatment period, COPD drugs prohibited by the protocol (except for salbutamol inhalation aerosol as a rescue drug) can be discontinued;
* Current smokers with a smoking quantity of ≥ 10 packs per year (smoking index (pack years) = daily smoking quantity (packs) × time (years), 1 pack = 20 cigarettes), or quit smoking for more than 6 months, or those with a history of exposure to other risk factors;
* Participants voluntarily sign the informed consent form；
Exclusion Criteria:
* Have a history of life-threatening COPD, including being admitted to the intensive care unit and/or requiring intubation;
* Have received treatment for COPD acute exacerbation for pneumonia within 12 weeks before screening;
* Have a history of or currently have severe cardiovascular diseases;
* Have type I diabetes or poorly controlled type II diabetes (fasting blood glucose ≥ 10 mmol/L at screening);
* Have cancer (in situ cancer that has been cured for more than 5 years, skin squamous cell carcinoma and basal cell carcinoma, etc., except for subjects with suspected malignant tumors or undetermined tumors);
* Combine other severe unstable kidney, nervous system, endocrine diseases, thyroid diseases, urinary system, ophthalmic diseases, immune system, mental system, gastrointestinal, liver or blood system disease/abnormal history, as determined by the investigator, participation in this study may pose risks to the subjects or affect the analysis of research results;
* During the screening period (visit 1), the investigator determines that the laboratory tests of the subjects show clinically significant abnormalities that may pose risks to the subjects;
* Allergy to HSK39004 inhalation powder or salbutamol or any known components in the administration system ; 8. Before the pulmonary function test during the screening (visit 1), any prohibited drugs in the protocol were used;
* During the screening period, there were clinically significant abnormalities in the 12 lead electrocardiogram that were determined by the researchers to be potentially risky for the subjects;
* Had major surgery (requiring general anesthesia) within 6 weeks before screening, not fully recovered at the time of screening, or planned to undergo surgery before the end of the study;
* Pregnant or lactating women, or female subjects with positive pregnancy test results;
* Researchers determine other subjects who are not suitable to participate.
