Abstract: objective:to compare the image quality and the display of the structure of normal lung between lung CT targeted reconstruction (local small FOV thin layer CT imaging) and conventional lung CT. Methods:74 cases of subjects respectively routine pulmonary CT scan (5mm) and targeted reconstruction (FOV:20 cm, thickness:1.25mm). Two radiologists respectively determine normal lung CT imaging, targeted reconstruction image quality:pulmonary lobule structure, pulmonary vessels and bronchial branches display (grade 1~4) and judge the strength of confidence. The targeted reconstruction with 1.25-mm sections and small FOV showed more was used as the gold standard. and further determine the sensitivity of targeted reconstruction and conventional lung CT scan imaging (5mm), the consistency between two observers to make Kappa test. Results:Level 1 and 2 image quality of conventional lung CT scan and targeted reconstruction showed no significant statistical differences. Level 3 and level 4 image quality, targeted reconstruction is superior to the conventional lung CT scan, the differences between two observers was statistically significant (P<0.05); According to the targeted reconstruction imaging, Conventional pulmonary CT scan imaging (5mm) Level 3 image's sensitivity was 97.1%, 98.6%, respectively; Level 4 image's sensitivity was 80.8%, 85.3% respectively. And diagnostic confidence level increased significantly (P<0.05). Image quality judgment has a good consistency for targeted reconstruction, conventional lung CT between two observers (k=0.717, 0.746). Conclusion:Compared with conventional CT images, targeted reconstruction images can increase the normal display rate of pulmonary microstructure, the confidence of the judgment.