Inclusion Criteria:  Patients diagnosed with bronchiectasis (according to the Chinese consensus, patient's previous chest CT examination must show bronchiectasis). Patients with age ≥18 years old.  Exclusion Criteria:  Bronchiectasis due to known cystic fibrosis. With acute bronchiectasis exacerbation within 4 weeks before enrolment. Participated in any interventional clinical trial within 6 months before enrolment. Patients who are unable or unwilling to provide informed consent.