Objective To observe and explore the predictive value of enhanced CT scanning in the diagnosis of hemorrhagic transformation after large area cerebral infarction. Methods 47 cases with large area cerebral infarction from 2013 January to 2014 June in our hospital were selected. All patients were hospitalized within 12 hours and given emergency head CT scanning. Head plain CT scan and enhanced CT scan were performed within 24-48h, and plain CT scan was performed after 7days. The correlation between contrast agent extravasation and cerebral hemorrhage transformation was observed and analyzed. Results In 47 cases, 17 cases showed old cerebral infarction, 12 patients showed focal changes and other patients showed no obvious abnormalities. 24- 48h after onset of infarction, plain CT scan showed that all 47 patients were found large area of cerebral infarction, in which 2 cases were found hemorrhagic transformation and the remaining 45 cases underwent enhanced CT scan showed contrast agent extravasation in 11 cases. Patients who underwent enhanced CT scan were performed with plain CT scan within 1 week and found that 15 cases showed hemorrhagic transformation; 11 cases with contrast agent extravasation showed high density changes in infarction focus by reexamined plain CT scan. In all cases, 17 patients were found hemorrhagic transformation (36.17%), in which 11 cases were predicted by enhanced CT scans, and the predictive accuracy was73.33%. Conclusion The application of contrast enhanced CT scan on the basis of head plain CT scan on large area acute cerebral infarction patients could help the early discovery of cerebral hemorrhagic transformation, rapid diagnosis, treatment scheme adjustment and the prognosis and outcome of disease.