Evaluate the respiratory function in 78 chronic obstructive lung disease (COPD) patients at Department of Respiratory and Allergonogy in Friendship Hospital for two years 2008-2009. The results showed that: there were 67.95 percent of the COPD patients who have airway obstruction, 20.51 percent mixed airway obstruction patients, 11.54 percent who was restrict airway obstruction. Besides, the evaluation index of airway obstruction such as: FEV1, FEV1 percent, PEF, MEF...were reduced along the diseases time (5 years) with p 0.01. So, the respiratory function were reduced along the desease time.