Inhaled budesonide (adrenocorticosteroid) is the main treatment for asthma at this stage. Generally speaking, budesonide should be inhaled when asthma is persistent, and the dose of inhalation is: 200-500ug per day for mild asthma; 500-1000ug per day for moderate asthma; 1000ug or more per day for severe asthma. The dose should be changed to maintenance dose after the symptoms are relieved. In case of intermittent attacks, it is not necessary to inhale budesonide, but only to apply Ventolin to control the symptoms. Intermittent: symptoms < once a week, nocturnal asthma symptoms ≤ 2 times a month. Mild persistent: symptoms ≥ once a week but < once a day, nocturnal asthma symptoms > 2 times a month but < once a week. Moderately persistent: daily symptoms that interfere with activity and sleep, nocturnal asthma symptoms ≥ once a week Severe persistent: daily symptoms, frequent, frequent nocturnal asthma symptoms, limited physical activity