Objective: To explore the value of high-resolution CT in the diagnosis of early lung adenocarcinoma and analyze the significance of CT signs in the evaluation of its infiltration. Methods: A total of 600 patients with early lung adenocarcinoma admitted to our hospital from June 2019 to June 2020 were selected as the study object, including 370 cases in a non invasive group and 230 cases in an invasive group. All the lesions were scanned with high-resolution target. The size, density, and distribution of the lesions in the two groups were compared, and their CT signs were analyzed. The influencing factors of infiltration of lung adenocarcinoma were analyzed. Results: Compared with the non invasive group (8.1±1.8) mm, the maximum diameter of lesions in the invasive group (8.7±1.2) mm was larger, the difference was significant (P<0.05). The incidence of burr sign (23.9% vs 16.2%), pleural indentation sign (21.7% vs 13.5%), and vascular fasciculation sign (16.5% vs 10.5%) were higher in the invasive group than those in the non invasive group (P<0.05). Multivariate logistic analysis showed that the largest diameter (>8.51 mm), presence of burr sign and presence of vascular cluster sign were the risk factors for infiltration of sub-centimeter pure ground-glass opacity lung adenocarcinoma. ROC analysis showed that the area of infiltration was 0.886, 95%CI: 0.791 to 0.941, the sensitivity was 83.8%, the specificity was 77.9%, and the Youden index was 0.617. Conclusion: High-resolution CT can show all kinds of signs of early lung adenocarcinoma more clearly. In the lung adenocarcinoma lesions appearing as sub-centimeter pure ground-glass opacity nodules, when the diameter of the lesions is more than 8.51 mm, or spicule sign or vessel convergence sign is presented, its infiltration should be highly suspected.