The pathogenesis of chronic obstructive pulmonary disease(COPD) involves inflammation，oxidative stress，and protease-antiprotease imbalance，among which the protease-antiprotease imbalance is one of the main mechanisms of COPD.Increased protease can damage the lung tissue by participating in inflammation，degrading extracellular matrix，and remodeling airway.In recent years，a large number of clinical trials and basic studies have been carried out with protease-antiprotease imbalance as a breakthrough point，accumulating fruitful results.