Objective To evaluate the dose reduction technology using in CT-guided percutaneous lung biopsy of pulmonary lesions using automated core needle biopsies (ACNB).Methods 412 ACNB cases included 146 consecutive conventional patients (group A,120 kV/100 mA) and 266 consecutive patients (group B,120 kV/20 mA,low-dose scanning,reduce scanning width and scanning frequency).The quality of images was compared by grain homogeneity,fine structure,clearness of tissue interface and artifacts.The total diagnostic accuracy rate,the examination time and radiation dose between group A and group B were compared.Results The fine structure of group B was significantly lower (X~2 ＝7.0508,P ＜ 0.05).The total diagnostic accuracy rate was 95.9% vs 95.1% (X~2 ＝0.1296,P ＜ 0.05).The examination time for biopsy procedure was (16 ±2.2)min vs (15.9 ±2.0)min (t ＝ 1.3579,P ＜ 0.05) ,and the mean effective dose (E) was (1.74 ± 0.7) mSv vs (0.59 ± 0.14) mSv (t ＝ 19.3415 ,P ＜ 0.05) .The E of group B decreased by 66%.Conclusions ACNB is a feasible and accurate method for diagnosing pulmonary lesions,and the E can significantly reduce the dose received in low-dose scanning.