Abstract： Objective To evaluate the role of surgical lung biopsy (SLB) in the management of diffuse interstitial lung disease (DILD) with no specific diagnosis.Methods We conducted a retrospective analysis of 179 cases with DILD of non-specific diagnosis after non-invasive methods and minimally invasive processes,including bronchoscopy and CT-guided lung biopsy,were performed SLB at Peking Union Medical College Hospital between 2006 and 2012.Patient demographics,surgical approach,number and site of biopsies,post-operative complications and postoperative pathological diagnosis and treatment were analyzed.Results Of 179 cases,there were 91 males (50.8％) and 88 females (49.2％),with a median age of 47.3 years (range 16-76).There were 6 cases(3.4％) who were younger than 20 years and 25 cases(14％) older than 60 years.From 2006 to 2012,every year there were 16 case (8.9％),17 cases (9.5％),19 cases(10.6％),44 cases(24.6％),33 cases(18.4％),31 cases(17.3％) and 19 cases (10.6％) respectively.The total median hospital stay was 33.4 days (range 6-76) and the mean postoperative stay was 18.6 days (range 2-56).The mean duration for chest drainage was 3.2 days (range 2-18).Among them,150 cases were arranged with video-assisted thoracoscopy surgery (VATS) and 29 cases were arranged with minithoracotomy.The number of biopsies taken was ranged from one to four and there were 126 cases (70.4％) had more than one biopsy.The biopsy was performed in left lingular lobe (54 cases/30.2％),left natural upper lobe (16 cases/8.9％),left inferior basal segments (56 cases/ 31.3％),right upper lobe (30 cases/16.7％),right meddle lobe (40case/22.3％) and right inferior basal segments (56 case/31.3％) respectively.Definitive pathological diagnosis was reached in 103 cases (57.5％),diagnosis was reached after combination of pathological,clinical and radiological manifestations in 32 cases (17.9％) and there were 44 cases (24.6％) could not achieved diagnosis even after the SLB.Chronic extrinsic allergic alveolitis was the most common diagnosis (33/24.4％),following nonspecific interstitial pneumonia (27/20％) for the 135 cases with a definite diagnosis.Among 179 cases,there were 114 cases had a change in their treatment following the results of SLB.There were 16 cases had a fever after surgery and antibiotics were administrated for eleven of them.Other complication were included delayed wound healing (＞ 10 days after surgery,6 cases),thoracic hemorrhage (5 cases),chest tube re-indwelling because of pneumothorax (4 cases),delayed weaning of ventilator (＞ 3 days after surgery,4 cases),respiratory failure (3 cases),and thoracic infection (2 cases).There were two cases died within 30 days following surgery because of respiratory failure.Conclusions Most of the DILD patients who were arranged with SLB were young and middle-aged cases.The left lingular lobe,right meddle lobe and both inferior lobes were the preferred biopsy sites.The results of biopsy surgery could provides a diagnosis for most of the DILD patients and could modulate the treatment for more than half of them.Fever and delayed wound healing were the major complications.The SLB related mortality was low.SLB was suggested to the undiagnosed DILD patients.