Abstract: Objective:The study was designed to evaluate the efficacy and safety of the domestic inhaled budesonide in the treatment of mild to moderate asthma. Methods:In a multicentric, randomized, single-blind, parallel-controlled study, 132 patients with mild to moderate asthma were randomly selected to receive either of the following treatments for 4 weeks: 600mg/d of the domestic or the imported inhaled budesonide. The forced expiratory volume in one second （FEV₁） and the peak expiratory flow （PEF） were measured as the primary effective values. Results: The efficacy analysis: After a four-week treatment,①Lung function improvement:In both groups significant improvements in FEV₁ and PEF were found （P＜0.01）. Changes of FEV₁, PEF between two groups had no significant difference（P＞0.05）.②Airway hyperresponsiveness: PD₃₅-Rrs in both groups improved significantly（P＜0.05）, and changes of PD₃₅-Rrs between two groups had no significant difference（P＞0.1）. Safety evaluation: the main side effects of both medicines were throat irritation and hoarseness. The incidence rates of adverse events were similar between two groups （P＞0.05）. Conclusions: The domestic inhaled budesonide is an effective medicine to improve the lung function and airway hyperresponsiveness in the mild to moderate asthmatic patients. It is as effective and safe as the imported ones.