Objective To investigate the value of plain magnetic resonance imaging combined with diffusion-weighted imaging (DWI) sequence in preoperative evaluation of middle ear cholesteatoma. Methods A total of 26 patients with suspected middle ear cholesteatoma admitted to Luoding People′s Hospital from April 2020 to October 2021 were selected as the research objects. Preoperative magnetic resonance plain scan combined with DWI sequence and temporal bone CT+ 3D reconstruction were used for imaging examination. The diagnostic efficiency was evaluated by comparing with postoperative pathological results. Results Among 26 patients, 20 cases were pathologically confirmed as middle ear cholesteatoma. The sensitivity, specificity and accuracy of Mr Combined with DWI sequence in the diagnosis of middle ear cholastatoma were 95.0% (19/20), 83.3% (5/6) and 92.3% (24/26), respectively, which were consistent with postoperative pathological diagnosis (Kappa=0.783, P＜0.05). The sensitivity, specificity and accuracy of temporal bone CT+3D reconstruction in the diagnosis of middle ear cholastatoma were 55.0% (11/20), 50.0% (3/6) and 53.8% (14/26),and the consistency with postoperative pathological diagnosis was poor (Kappa=0.037, P＞0.05). The sensitivity of preoperative MRI combined with DWI sequence in the diagnosis of middle ear cholesteatoma was higher than that of preoperative temporal bone CT+3D reconstruction, and the difference was statistically significant (P＜0.05). Conclusion Magnetic resonance combined with DWI examination method has good qualitative diagnostic value for middle ear cholesteatoma, and also has certain reference value for localization diagnosis, which is of great significance for making a reasonable surgical plan before operation.