Abstract: We established in vitro evaluation methods of the nebulization characteristics of budesonide suspension for inhalation and analyzed the influence factors. The delivery rate and total drug substance delivered (TDD) of two manufacturers were determined by using the breath simulator with different nebulizers. The aerodynamic particle size distribution was investigated by next generation impactor (NGI) and HPLC as well. The fine particle dose (FPD), the mass median aerodynamic diameter (MMAD), the delivery rate and TDD results of the same sample with different nebulizers were significantly different (P < 0.01), mainly due to the different design parameters of the nebulizers. The FPD of two samples were significantly different (P < 0.01) by the same nebulizers, probably due to differences in physical and chemical properties differences such as suspension particle size. The analysis method of nebulization characteristics provided in this paper can be used to select the nebulization device with appropriate delivery dose and aerodynamic particle size distribution (APSD) for different inhalation liquid preparations in clinical practice, and can also be used as the guidance for the selection of nebulization device and analysis method in the research and development of generic inhalation liquid preparations and quality consistency evaluation.