Abstract: Objective To compare the value of digital radiography(DR)combined with multi-slice spiral CT(MSCT)or magnetic resonance imaging(MRI)in diagnosis of subacromial impingement syndrome(SIS). Methods The image data of 46 clinically diagnosed patients with SIS was retrospectively analyzed. The acromion shape and the shortest acromial humeral interval(AHI)between DR combined with MSCT and DR combined with MRI were compared. The image characteristics and diagnostic condition of SIS were compared. Results The detectable rates of the acromion shape and AHI of two methods were higher, but the difference was not statistically significant(P>0.05). The detectable rate of SIS by DR combined with MRI was significantly higher than DR combined with MSCT［97.8%(45/46)versus 69.5%(32/46), P<0.05］. The differences in sensitivity and Youden index of the two methods were significant(P<0.05), and the diagnostic specificities of the two methods were 100.0%. The detectable rates of SIS with Bigliani Ⅲ by two methods showed no significant differences(P>0.05). The detectable rates of SIS by DR combined with MRI for Bigliani Ⅰ and Bigliani Ⅱ were higher than DR combined with MSCT(P<0.05). The differences in detectable rate of SIS for AHI<5 mm by two methods were not significant(P>0.05). The detectable rates of SIS for AHI of ranging from 5 mm and above to less than 10 mm and AHI of 10 to 15 mm by DR combined with MRI were higher than DR combined with MSCT(P<0.05). Conclusion Compared to DR combined with MSCT, DR combined with MRI has a higher - accuracy in diagnosing SIS, it can clearly show the anatomy and morphology of acromia, ligament calcification, clearly present the anatomy of rotator cuff, and the direct and indirect signs of SIS such as the disease region and degree. Therefore, DR combined with MRI can provide more diagnostic information and more reliable imaging basis for clinical selection of treatment methods.