Abstract： Objective To summarize the lung HRCT findings of lung Langerhans cell histiocytosis (LCH) in children. Methods A total of 54 children with lung LCH pathologically proved in our institute from September 2006 to December 2014 were retrospectively reviewed. Patients were subdivided into two subgroups, diffuse type (n=29) and localized type (n=25). In addition, 32 children with LCH but without pulmonary infiltration were selected as control group. HRCT findings of 54 LCH with lung involvement were reviewed and analyzed for distribution pattern. The age of onset, illness duration and pulmonary function were compared between the lung LCH group and the control group. The differences of HRCT findings in LCH patients between diffuse type and localized type were compared with χ2 test. The differences on the onset age, illness duration and pulmonary function between the LCH group with lung involvement and control group were compared with non-parametric test(Mann-Whitney U Test). The differences of pulmonary function between the LCH group with lung involvement and control group were compared with Fisher exact probability test. Results The signs of pulmonary LCH on HRCT included lobular hyperinflation (n=26), interlobular septa thickening (n=11), cystic lesions (n=11), ground?glass opacity (n=10), nodules (n=9), and centrilobular nodules (n=6). The signs presented in 21, 8, 7, 9, 4 and 6 cases in diffuse type group respectively and 5, 3, 4, 1, 5, 0 in localized type group. Among them, lobular hyperinflation, ground?glass opacity and centrilobular nodules were more prevalent in the diffuse group. The&nbsp;difference was statistically significant (χ2=14.77,2.01,0.55,4.84,0.06 and 3.91, P<0.05). The onset age of LCH group with lung involvement was younger than the other (Z=-2.40, P<0.05). However, there was no statistically significant difference in the illness duration (Z=-1.46, P>0.05) and pulmonary function between two groups (P>0.05). Conclusions Lobular hyperinflation, ground glass opacity and centrilobular nodules are the most common manifestations in LCH patients with lung involvement and the distribution is mostly diffuse. Nodules, cystic lesions and interlobular septa thickening may exist. Several signs may coexist simultaneously. Younger children with LCH are more vulnerable to lung involvement.