Background: This study was in order to understand difference of the clinical characteristics and outcome between interstitial lung disease with dermatomyositis and idiopathic interstitial pneumonia. Methods: We performed a retrospective case-contral study in patients with ILD with DM or IPF from January 2003 to March 2014 in the third affiliated hospital of Sun Yat-sen University. Variables of interest included respiratory symptoms, HRCT features, distribution at CT, ICU stay, steroids therapy, immunosuppressive therapy, and the 90-day mortality. The study was approved by the Institutional Review Board of the hospital. Results: Of the 64 patients (44 ILD with DM and 20 were IPF), the main HRCT features were interlobular septal thickening (68.8%), intralobular reticular opacities(62.5%), non-septal linear or plate-like opacities(68.8%), honeycombing(32.8%). ILD with DM occurs more commonly in females (P 0.004). Between two groups gender, cough(P 0.02) was more frequent in ILD with DM group. Intralobular reticular opacities (P 0.013) and honeycombing(P 0.000) were more frequent in IPF group. Diffuse distribution at CT was more frequent in IPF group. Steroids therapy(P 0.000) was used more for ILD with DM. There was no difference in the 90-day mortality between groups. Conclusions: ILD with DM occurs more commonly in females. Cough was more frequent in ILD with DM group. Intralobular reticular opacities, honeycombing and diffuse distribution at CT were more frequent in IPF group. Although steroids therapy was used more for ILD with DM group, there was no difference in the 90-day mortality between groups.