To improve the remedial efficiency of anti-inflammation drugs such as astragalus polysaccharides (APS) via pulmonary inhalation.Inhalable astragalus polysaccharides /chitosan (APS/CTS) microspheres were designed to sustain drug release and provide drug protection.Chitosan were applied as carriers of microspheres to deliver APS to the desired sites in the lung by spray drying method using an Orthogonal Design.