Objective To investigate the clinical effects of high-field magnetic resonance diffusion weighted imaging in the transient ischemic diagnosis. Methods 97 cases of transient ischemic patients in our hospital from February 2013 to February 2015 were selected, in which 39 cases of progressive patients secondary infarction were selected as observation group A, and another 58 cases of early onset patients were set as observation group B, and 40 cases of healthy people at the same time were selected as the control group. All these samples were given high-field MR diffusion imaging and carotid ultrasonography, and the relationship between these two results were estimated, the application value of the method in the transient ischemic diagnosis was analyzed. Results The MRI lesion counts, diameter, carotid ultrasound intima-media thickness, each plaque incidence, thrombosis rate, moderate to severe stenosis rate in the observation group were all higher than those in the control group; these indicators except thrombosis rate in the observation group A were significantly higher than those in the observation group B, and MR diffusion imaging and carotid ultrasonography data showed a positive correlation, with statistical significance (P<0.05). Conclusion MR diffusion imaging and carotid ultrasonography data shows a positive correlation, and is valuable in the diagnosis of early onset and progressive lesions.