Objective: Our aim was to study whether the cellular bronchoalveolar lavage fluid (BALF) profile was associated with the parameters of pulmonary function tests. Methods：Lung function tests and BAL were carried out in 18 untreated, non-smoking patients suffering from sarcoidosis and 18 normal subjects. Results：（1）Lung function tests were normal at rest in patients with sarcoidosis（P＞0.05）, the single breath carbon monoxide diffusing capacity decreased (P＜0.05)，and the small airway function decreased too (P＜0.05).（2）The percentage of lymphocytes in BALF of sarcoidosis increased comparing with the normal subjects（P＜0.01），and the ratio of CD+4 to CD+8 in BALF increased significantly in sarcoidosis（P ＜0.05）, furthermore, the increase of both the percentage of lymphocytes and the ratio of CD+4 to CD+8 in BALF of sarcoidosis were well nagatively correlated with the decrease of the percentage of DLCO (r=-0.67, P＜0.01 and r=-0.55, P＜0.05, respectively), the decrease of mid-expiratory flow at 50% of vital capacity (FEF50%) was well correlated with the increase of the percentage of lymphocytes in BALF of sarcoidosis (r=-0.54, P＜0.05). Conclusion：Pulmonary diffusing capacity（DLCO) was significently correlated with BALF lymphocyte phenotype，so was small airway function，and can act as the marker of activity of sarcoidosis.