Objective To analyze the factors related to the occurrence of complications in performing CT-guided percutaneous lung biopsy with 18 G-Bard Magnum needle. Methods CT-guided percutaneous lung biopsy with 18 G-Bard Magnum needle was carried out in a total of 58 patients. The postoperative complications were recorded, and the related factors causing complication were analyzed. Results Successful puncturing was achieved in all patients with a technical success rate of 100%. Postoperative complications included pulmonary hemorrhage (n=11,19.0%), a little amount of bleeding in needle tract (n=7,12.1%), hemoptysis (n=3,5.2%), hemothorax (n=1,1.7%), and pneumothorax (n=10,17.2%). Chi-square test showed that the occurrence of pulmonary hemorrhage bore a close relationship to the lesion’s diameter, the distance between the lesion and the chest wall, the lesion’s location and times of puncturing (P<0.05). The occurrence of pneumothorax was closely correlated with the age, the distance between the lesion and the chest wall, the presence of perifocal emphysema, the lesion’s location and times of puncturing (P<0.05). Univariate analysis indicated that the postoperative complications were liable to occur in the patients whose imaging examination showed perifocal emphysema and lung hilar lesion, and who had more than two independent risk factors (P<0.05). Conclusion CT-guided percutaneous lung biopsy with 18 G-Bard Magnum needle is an accurate and safe technique with relatively higher positive diagnosis rate, but this technique should be carefully used in patients who has perifocal emphysema, or lung hilar lesion, or more than two independent risk factors.(J Intervent Radiol, 2015, 24:792-796)