Objective?To analyzed the diagnostic value of multi-slice spiral CT in the diagnosis of focal ground glass density pulmonary nodules. Methods?From November 2018 to June 2020，60 patients with focal ground glass density nodules in the lung were selected from Kunshan First People's Hospital，They were divided into two groups according to the pathological diagnosis，with 30 cases each group. The experimental group was malignant lesion and the control group was benign lesion，the results of the two groups were compared. Results?The proportion of patients with lesion size ＞ 3.0 cm in the experimental group was significantly higher than that in the control group，and the proportion of patients with 1.0 ～3.0 cm and ＜ 1.0 cm were significantly lower than that of the control group，the difference was statistically significant（P ＜ 0.05）；the proportion of lobulated，round and irregular lesions in the experimental group were significantly higher than that in the control group，while the proportion of patchy lesions in the experimental group was significantly lower than that in the control group，and the difference was statistically significant（P ＜ 0.05）；the proportion of patients with air bronchogram，pleural thickening and pleural indentation in the experimental group was significantly higher than that in the control group（P ＜ 0.05）. Compared with the control group，the proportion of patients with fuzzy edge in the experimental group was significantly lower than that in the control group，and the proportion of patients with rough，burry and smooth edges was significantly higher than that of the control group（P ＜ 0.05）. Conclusion?In the diagnosis of pulmonary focal ground glass density nodules，multi-slice spiral CT diagnosis can well distinguish the benign and malignant pulmonary focal ground glass density nodules，with high diagnostic accuracy，and can provide effective basis for the follow-up treatment.