Objective To investigate the diagnostic value of CT thin-section target reconstruction technique in patients with pulmonary small size groud glass nodules (sGGN).Methods A total of 109 patients with pulmonary sGGN certified post-operation and/or follow up were analyzed retrospectively,and the clinical and CT images of all patients were completely collected.There were 23 cases of benign group,21 cases of adenocarcinoma in situ group,29 cases of minimally invasive adenocarcinoma group and 36 cases of invasive adenocarcinoma group,respectively.The differential diagnostic value using CT thin-section target reconstruction technique was analyzed between the benign and malignant pulmonary sGGN groups,and the CT feature detection rates were compared between CT thin section target and common reconstruction techniques.Results The CT thin-section target reconstruction technique had improved the diagnostic efficiency of pulmonary sGGN.The diagnostic accuracy,area under curve(AUC),sensitivity and specificity were 85.32 ％,0.679,90.80 ％,63.64 ％ in malignant group and 77.06％,0.764,83.72％,52.17％ in benign pulmonary sGGN group,respectively.The CT features as solid component in whole nodule,"halo sign",speculation sign,pleural retraction sign,lobulation sign were more detected by using the thin-section target reconstruction technique than that by using the common reconstruction among adenocarcinoma in situ group,minimally invasive adenocarcinoma group and invasive adenocarcinoma group (P＜0.05) but not speculation sign in the invasive adenocarcinoma group(P=0.126).Conclusion The CT thin section target reconstruction technique can improve the diagnostic value of pulmonary sGGN.