Objective An approach to detection and signs of peripheral lung cancer and inflammation nodules below 2cm between MSCT conventional scanning and HRCT scanning, to improve the accuracy of the diagnosis and differential diagnosis. Methods 73 cases with peripheral lung cancer and 32 cases with inflammatory nodules under 2cm which were confirmed by pathology and clinical were collected, 7mm thick and 1mm thick HRCT were used respectively to scan, analyzing the density of lesions, bubble signs, air bronchograms, edge of lession, lobulation, spiculation,pleural indentation,small spines, fuzzy shadow around the lesions, and strengthen signs. Results Compared lung cancer signs with inflammation nodules signs, the detection of 7mm thick imaging is significant difference(P<0.05), the detection of 1mm thick HRCT signs betweem lung cancer and inflammation nodules is significant difference(P<0.05), compared 7mm thick imaging with 1mm thick imaging, the detection of lung cancer signs is significant difference(P<0.05), compared 7mm thick imaging with 1mm thick imaging ,the detection of inflammation nodules signs is without significant difference(P>0.05). Small spines, lobulation, spiculation,pleural indentation were often found in lung cancer. Conclusion 1mm thick HRCT scanning shoud be as a preferred check technology in differentiating peripheral small lung cancer and inflammation nodules, especially with important value for the diagnosis of small lung cancer