Objective To analyse the dynamic changes of peripheral small lung cancer on CT images in different periods and to summarize its morphological features so that improving the diagnosis level.Methods The CT images of 30 cases with peripheral lung cancer confirmed by pathology and cytology were analysed retrospectively.Results Most peripheral small lung cancer appeared as nodule,their average diameter was 17 mm.9 cases showed homogeneous density and another 9 cases were appeared as aggregation by small multi-nodule.6 cases were slight lobulated and another 6 cases had short spiculation.A few of the cases revealed nontypical lobular shadows which were easily diagnosed inflammations.With dynamic observation,all the lesions showed typical peripheral lung cancer features including like nodule,growth gradually,lobulated and speculate brim and pleura retraction.Conclusion If the small nodules (diameter