Objective To evaluate the clinical value of quantitative analysis of CT histogram in differentiating benign and malignant pulmonary grind glass nodule. Methods A total of 123 cases of pulmonary focal milled glass density nodules from January 2016 to December 2017 were selected to be scanned by PHILPS 64 row spiral CT instrument. The clinical value of CT histogram quantitative analysis was used to identify the benign and malignant pulmonary nodules. Results (1) There was no significant difference in lesion size between benign and malignant lesions(P>0.05). In the shape of lesions, benign lesions were significantly less than those of malignant lesions with spherical, lobulated and irregular shapes, P<0.05).(2) There was less burr and lobulation than malignant lesions on the edge of the lesion, and the boundary between the lesions was more clear than the malignant lesion, and the difference was statistically significant. (P<0.05). (3) the PET/CT - SUVmax value between the benign and malignant lesionshas no obvious difference, P> 0.05.(4) compared with malignant lesions, the average CT value and peak value of benign lesions were significantly higher, P<0.05). Conclusion Multi slice spiral CT is effective in the diagnosis of focal pulmonary ground glass density nodules, and has high accuracy in determining the nature of fGGO lesions.