Objective To observe the application of low dose CT scanning in lung puncture biopsy,and to discuss the feasibility and limitations.Methods 100 cases of CT guided percutaneous lung biopsy,used SPSS soft-ware to generate random numbers,odd number into the routine dose group,even number into low doses study group. The routine dose group of 50 patients underwent routine dose CT scanning(200mA,reconstruction thickness 2.0mm, pitch 16mm/rot)and puncture,and the low doses study group were given low dose CT scanning in 50 patients (10mA,reconstruction thickness 2.0mm,pitch 23mm/rot)and puncture.Two groups after routine disinfection punc-ture,were taken tissue samples for pathological examination.The two groups of CT scanning dose and image quality, the success rate of puncture and complications were compared.Results The success rate of puncture in conventional dose scan group was 90.00%;CT dose index weighted index CTDIw was (23.64 ±5.91)mGy;the average dose length product DLP was (172.31 ±43.08)mgy ×cm.The success rate of puncture of the low doses study group was 84.00%;CTDIw was (1.22 ±0.31)mgy;DLP was (8.56 ±2.14)mgy ×cm.The successful puncture rate of the two groups had no significant difference(χ2 =0.638 9,P=0.374 2);The radiation dose was statistically significant(CTDIw compare:t=2.798 3,P=0.005 4;DLP compare:t=2.684 9,P=0.007 8);The image quality can meet the need of puncture biopsy;At the same time,the two groups had no severe complications.Conclusion Low dose than routine dose CT scanning in lung biopsy success rate has no difference,but which can significantly reduce the radiation dose.