Objective To study clinical application value of MRI in the diagnosis of diffuse cerebral axonal injury,and provide a reference for clinical diagnosis in the future,also improve the diagnosis level of diffuse cerebral axonal injury. Methods Seventy six patients with diffuse cerebral axonal injury patients admitted by this hospital from January, 2010 to October, 2014 were selected as research subjects, who were divided into two groups according to different methods of diagnosis, patients in the control group were subject to CT examination, and patients in the observation group were subject to examinations with magnetic resonance imaging (MRI), diagnosis results of patients in two groups were compared. Results The detection quantity of deep cerebra area, non-bleeding lesions and bleeding lesions of patients in the observation group were significantly higher than that of patients in the control group, p<0.05, and the diagnosis sensitivity of patients in the observation group was higher than that of patients in the control group, p<0.05, and the difference was statistically significant. Conclusions Both CT and MRI pose important clinical diagnostic value in the diagnosis of diffuse cerebral axonal injury, but the diagnosis sensitivity of MRI is higher than that of CT, especially the sensitivity of non-bleeding cerebral lesions and deep lesions is higher that of CT, and it delivers more significant advantages when compared to CT examination technology, being worthy of wide application and promotion in clinical practices.