Objective To explore the efficacy of double-slice helical CT and 0.3 T MRI applied in clinical diagnosis on early cerebral infarction and to evaluate its application value. Methods Sixty four patients with cerebral infarction admitted by the department of neurology of the Hospital from March, 2013 to March, 2015 were selected, who were defined into the control group (32 cases, double-slice helical CT) and the observation group (32 cases, 0.3 T MRI) within 6 hours of the onset according to different diagnostic methods. Positive detection rate and diagnosis accuracy, lesions imaging manifestations of patients in two groups were compared. Results The diagnosis accuracy (96.9%) on patients in the observation group satisfied P<0.05 when compared to that of patients in the control group (68.8%), and the difference was significant. The comparison in positive detection rate of basal ganglia, internal capsule, frontal, parietal lobe, brain stem and thalamus and cerebellar lesionχ2 satisfied 5.02, 3.95, 34.71, 4.16, 4.13, 3.99 and 4.13 (P<0.05), the differences were statistically significant. The resolution of MRI image was better than that of CT image. Conclusions MRI diagnosis on early cerebral infarction deliver advantages including strong sensitivity, high resolution and clear image, improve diagnostic accuracy and positive rate of examination on lesions, which facilitate timely treatment of patients and impose high clinical value.