Objective To discuss the clinical value of improved percutaneous lung biopsy under CT guidance.Methods Reviewed the clinical data of 80 cases of improved percutaneous lung biopsy under CT guidance,which were confirmed by surgery or pathology.When took the operation,18 G semi-automatic cutting biopsy needle (made in American Cook's company) was used to improve the ways of positioning scan,two-step method of insert the needle,and the cutting technique of coaxial in each direction.Results All of the 80 patients were successfully completed pathological biopsy,successful rate was 100.0％ (80/80),and diagnosis rate was 98.8％ (79/80),incidence of complication was 10.0 ％ (8/80),all of these patients were recovered after treatment 2-5 d.Conclusion The method of improved percutaneous lung biopsy under CT guidance is safe,effective,simple and practical,which has high successful rate and low complication rate,the generalizability is certain.