Chitosan and a-cyclodextrin were used to prepare microspheres with theophylline for pulmonary delivery by spray drying method.The characteristics,mucociliotoxicity,permeation rate and drug release were studied.The drug entrapments of microspheres Ⅰ,Ⅱ and Ⅲ were from 35.70%to 21.09% and 13.33%.while yields and encapsulation efficiencies were higher than 45%and about 90%respectively.with smooth or wrinkled surface surfaces.FT-IR demonstrated theophylline had formed hydrogen bonds with chitosan and a-cyclodextrin.The mierospheres could effectively reduce the ciliotoxicity and easy to penetrate the memberine.The in vitro release of the microspheres was related to the ratio of drug/polymer and microspheres Ⅱ had a prolong release,providing the release of 72.00%in 12 h.The results suggestes that chitosan/ a-cyclodextrin microspheres Ⅱ are a promising carrier as sustained release for pulmonary delivery.