Abstract: Objective: To evaluate the application of MRI(magnetic resonance imaging) in the diagnosis of cerebral ischemic foci and brain atrophy and ischemic foci and the assessment of the risk of Alzheimer's disease(AD). Methods: 40 health people as group A, 40 patients with ischemic foci were group B, 40 patients with cerebral atrophy and ischemic foci and 40 AD patients were enrolled in our hospital from January 2016 to December 2016. All the cases were examiningd with MRI Diagnose and evaluate the differences in MRI images. Results: The ICA:PDV, R-ICA:MF of group C were significantly lower than those of group A and group B(P<0.05), ICA:PSV of group C was significantly lower than group B(P<0.05), but there were no significantly difference(P>0.05). The L-IJV:PDV of group C were significantly lower than in group A and group B(P<0.05). The MRI thickness of the four groups was significantly higher than that of the control group(P<0.05). The MRI thickness of the three groups was significantly higher than that of the control group(P<0.05), and the difference was statistically significant(P<0.05) Olfactory cortex(EC) and right hemisphere PCC linear trend were significantly different(P<0.05). Conclusion: Ischemic foci and brain atrophy are the result of different stages of brain tissue pathological changes.MRI diagnostic accuracy is higher, and the merge focal ischemic brain atrophy patients MRI images are similar to AD patients, and it can suggest the risk of AD, which has important clinical guiding value.