Bronchial asthma is a common chronic respiratory disease. Clinical studies have shown that standardized diagnosis and treatment of asthma, especially effective management, are important for improving the asthma control and the quality of life of patients. The guideline for the prevention and treatment of bronchial asthma (2020 edition) were based on the previous guidelines for the prevention and treatment of asthma in China and combined with the results of evidence-based medicine research at China and other countries/regiongs in recent years. The guideline is intended to provide guidance documents for improving the understanding and standardized diagnosis and treatment of asthma among medical doctors in China.