Chronic obstructive pulmonary disease(COPD) is one of major cause of morbidity and mortality worldwide. Cigarette smoking is the main risk factor for the development of COPD and causes airway inflammation and parenchymal destruction. In the pathogenesis of COPD, protease-antiprotease imbalance is considered to be one of the important processes through the study of alpha 1-antitrypsin deficiency. At present, not only neutrophil elastase but also cathepsin and matrix metalloproteinases produced by inflammatory cells are demonstrated to be important in the pathogenesis of COPD, In this review, the roles of various kinds of proteases in the airway inflammation are summarized.