Abstract: The size and surface morphology of carrier lactose had influence on the aerosolization performance of dry powder inhalers. In this article, chlorpheniramine maleate was blended with two types of commercial carrier lactose, which were Lactohale 100^® and Respitose SV003^® (SV003), as formulation model. In vitro experiments were conducted using fast screening impactor at 30 L·min^-1 and 60 L·min^-1 respectively. Meanwhile, computational fluid dynamics (CFD) coupling with discrete element modelling (DEM) was applied to discuss the movements of those two carrier particles in Handihaler^® at the flow rate mentioned above. The dispersion characteristics of two formulations and the dispersion mechanism of Handihaler^® were analyzed by establishing the relationship between in vitro experiments and numerical simulation. The results of in vitro experiments and CFD-DEM demonstrated that the aerosolization performance of formulation with SV003 was better. The linear correlation (R²=0.940 1) between fine particle dose and total energy loss by carrier collision within the wall of device was found by comparing the in vitro experimental results with CFD-DEM results. It revealed that particle-wall collision in Handihaler^® had direct impact on the dispersion results of formulation.