Abstract: Objective To analyze the characteristics of CT images of micro-nodules（≤10 mm in diameter） and explore their qualitative diagnostic value. Methods Multi-slice spiral CT images of 102 pulmonary micro-nodules in 87 patients with pulmonary micro-nodules，pathologically confirmed from March 2017 to November 2018，were retrospectively analyzed. Results Among 102 pulmonary micro-nodules，25 was included in the benign group，27 in the precancerous group and 50 in the malignant group. The incidence of nodal density，burr sign，lobular sign，vascular bundle sign，and pleural indentation sign of the three groups were statistically significant（P<0.05）. Vascular bundle signs in the benign and precancerous groups appeared mainly as clinging or passing through without thickening and distorting，while the malignant group showed mainly passing through with thickening and distorting. There was significant difference in vascular thickening and contouring in the three groups（χ²=19.103，P＜0.001）. However，no significant difference was found in the location of nodules，the occurrence of lung-tumor interface，and vacuole sign among the three groups（P＞0.05）. Conclusions CT images of pulmonary micro-nodules have certain characteristics，and possess important value in the diagnosis of pulmonary micro-nodules.

Key words: Pulmonary micro-nodules, CT, Imaging features, Diagnosis