Objective To assess the clinical diagnosis value of CT guided transthoracic core needle biopsy in patients with pathological changes.Methods The pathological diagnosis was performed after getting the tissue by the groovy needle punctured the lesion.Results The 165 patients included 153 focal pulmonary diseases and 12 diffuse pulmonary diseases,the defined pathological diagnostic rate was 92.1%,false negative rate was 3.9%,18.9%in malignant and benign pathological changes;and complication presented in 33.3%,pneumothorax,bleeding,hemoptysis and hypodermic haematoma were 17.0%,7.9%,7.3%and 1.2%,respectively.Conclusion The technique of pulmonary percutaneous biopsy under CT guided is a perfect method for qualitative diagnosis of difficult pulmonary pathological changes:it is of great clinical application.