Airflow limitation is common exist in idiopathic bronchiectasis patients. However, there are few evidence on the treatment of bronchodilator in bronchiectasis with airflow limitation. The efficacy and safety of dual bronchodilator in idiopathic bronchiectasis with airflow limitation are still unclear. Thus, the investigators conduct a multicenter, open-label randomized controlled trial to investigate the efficacy and safety of dual bronchodilator in idiopathic bronchiectasis with airflow limitation.

Airflow limitation is common exist in idiopathic bronchiectasis patients. Our previous studies showed that FEV1<50% is one of the major risk factors for poor prognosis and high incidence of acute exacerbation in patients with bronchiectasis. However, there are few evidence on the treatment of bronchodilator in bronchiectasis with airflow limitation, and there is no recommendation in bronchiectasis guidelines. Moreover, because of the high risk of infection and bacterial colonization in bronchiectasis, there is still unclear whether inhaled corticosteroids or bronchodilators affect the parameters of bronchiectasis. Thus, there is urgent need to optimize the treatment of bronchiectasis with airflow limitation.

Inclusion Criteria:

• Idiopathic bronchiectasis with FEV1/FVC < 70%

Exclusion Criteria:

• With Asthma
• α-1 antitrypsin deficiency
• Turculosis
• Lung cancer
• Sarcoidosis
• Idiopathic pulmonary fibrosis
• Primary pulmonary hypertension
• Uncontrolled sleep apnea
• Bronchiectasis accepted long-term low dose macrolides
• Pulmonary surgery within 6 months
• Lower respiratory tract infections require antibiotic treatment in 6 weeks
• Upper respiratory tract infection did not recover for at least 7 days
• With Glaucoma or severe prostate hyperplasia that can not use Indacaterol
• Patients allergic to experimental drugs
• Women pregnant, breast-feeding or who planned a pregnancy during the study