Objective To explore the tested results for the patients with acute phase of ischemic cerebral infarction by computed tomography and magnetic resonance imaging. Methods CT scan and MRI scans on the patients.Observe patients detected cases number, size, time, lesion diameter size, pathological parts and signs. Results 60 cases, CT will not be able to check disease within 6 h AICI, MRI detected 21 cases, Within 6 to 24 h CT detection in 2 cases, MRI detected in 35 cases, two methods of comparison, the difference was statistically significant (P<0.05), 1-3 DCT detected 19 cases, MRI detected 20 cases, two methods of comparison, there was no statistically significant difference (P>0.05). 60 cases of patients, with the progress of the disease, MRI and CT images show a dramatic increase in the number of lesions, but there is significantly higher than CT, MRI detected lesions to the difference was statistically significant (P<0.05). MRI and CT of lesion detection ability was statistically significant (P<0.05). CT signs include parenchymal density reducing groove, fuzzy and grey matter interface crack and brain pool becomes shallow, disappear, etc.MRI signs include DW1 sequence high signals, and high FLAIR sequence arterial line samples. Conclusion It has good diagnosis for the patients with acute phase of ischemic cerebral infarction by magnetic resonance imaging, find the condition at the, number of lesions, lesion detection ability, the effect is better, it has high values on clinical application.