Objective To study the evaluation and clinical significance of diffusion weighted imaging (DWI) and magnetic resonance angiography (MRA) in vascular lesions of patients with acute cerebral infarction (ACI). Methods 94 cases of ACI diagnosed patients were selected and given DWI and MRA examinations. The examinations results were analyzed. Results There were 63 single lesions and 31 multiple lesions in 94 patients after diagnosis, and the NIHSS scores were (12.86±2.97) points and (8.72±1.64) points respectively before and after treatment (P<0.05). 92 cases (97.87%) were positive by DWI, and there were significant differences in ADC value of bilateral brain tissue (P<0.05), and the ADC value and rADC of the affected side were first decreased significantly (P<0.05) and then increased significantly after 24h (P<0.05). 89 cases (94.68%) were positive by MRA examination. The degree of vascular stenosis was positively correlated with rADC, and was positively correlated with the NIHSS score before treatment, and was positively correlated with the difference value of NIHSS score before and after treatment. The rADC was positively correlated with NIHSS score before treatment, and was positively correlated with he difference value of NIHSS score before and after treatment. Conclusion DWI can clearly show the location of early lesions and the degree of ischemia in ACI patients. MRA can accurately locate the responsible vessels and its stenosis degree that lead to infarction. The combination of the two can be helpful for the early diagnosis and assessment of ACI, and can provide a theoretical basis for clinical treatment, thereby helping patients receive timely interventions to ease the disease and improve prognosis.