Objective：To analyze the diagnostic value of magnetic resonance imaging DWI and computed tomography (CT) in patients with chronic middle ear mastoiditis. Ｍethod:A total of 88 patients with chronic craniocerebral ear mastoiditis in Chuxiong People's Hospital from February 2019 to July 2022 were selected, and all of them received CT and MRI examination before surgery. Compare CT and MRI for the detection of chronic middle ear cholesteatoma mastoiditis.Analysis of CT and MRI manifestations of patients with chronic middle ear mastoiditis.With surgical pathologic examination results as the gold standard, compare MRI- DWI, CT can cholesteatoma lesions in patients with chronic middle ear mastoiditis accuracy and sensitivity, specific degrees.The consistency of MRI-DWI, CT and pathological examination was analyzed.Result:The sensitivity, specificity and accuracy of CT were 51.7%, 83.1% and 72.7% respectively.The Kappa value of consistency test between CT and surgical pathological examination results was Kappa = 0.360, P=0.001. There was a statistical difference in Kappa value, indicating low consistency .The sensitivity of MRI-DWI was 62.1%, the specificity was 89.8%, and the accuracy was 80.7%, The consistency test between the results of MRI-DWI and surgical pathological examination was Kappa =0.543, P<0.001, and there was a statistical difference in Kappa value with moderate consistency.Conclusion:The diagnostic value of MRI-DWI in cholesteatoma of chronic middle ear mastoiditis is higher than that of CT, and CT provides better spatial positioning. The two are complementary technologies, and the combined application of the two can provide better preoperative evaluation of cholesteatoma and ossicular chain status, and provide certain guidance value for the surgeon to choose a better surgical method and approach.