Bronchial asthma is the most common chronic respiratory disease in children. At present, more attention has been paid to the treatment of airway inflammation and smooth muscle spasm, while the related research on the risk factors of asthma attack, mucus plug formation and its effect on asthma has been ignored. This study was a retrospective study. Children hospitalized for acute exacerbation of asthma from 2016 to 2021 were selected as the research objects. The clinical manifestations, bronchoscopy results and lung CT results of children hospitalized for acute exacerbation of asthma were summarized. To analyze the risk factors of acute exacerbation, clinical characteristics, risk factors of mucus plug formation in hospitalized children with asthma, and the safety and efficacy of flexible bronchoscopy in the diagnosis and treatment of hospitalized children with asthma. The discharged children were investigated by written or online questionnaires to understand the acute attack of asthma, control level, compliance, appliability of the China Children's Asthma Action Plan, family management and medical utilization of children with asthma after discharge.