Objective To analyze multi slice spiral CT features and related risk factors of hemorrhagic transformation after cerebral infarction. Methods 80 patients with cerebral infarction treated in our hospital from January 2013 to November 2014 were selected as the research objects, patients underwent brain CT scan on onset 1-2d, patients with hemorrhagic transformation were included in study group (n=40), patients without hemorrhagic transformation were included in the control group (n=40), multi slice spiral CT inspection results of hemorrhagic transformation after cerebral infarction, classification and performance were observed, diagnostic sensitivity, specificity and accuracy of multi slice spiral CT and enhanced CT scanning were estimated, related risk factors of hemorrhagic transformation after cerebral infarction were single factor analyzed and multiple factor Logistic regression analyzed. Results Enhanced CT scan showed HT were large low density range punctiform, en plaque, strip, lumpy, scattered irregular shape high density range with uneven density, edge was not very clear, which were divided into peripheral type, central type, mixed type; sensitivity of enhanced CT in the diagnosis of HT 71.43%, accuracy 72.50% were significantly higher than multi slice spiral CT (54.29%, 50.00%) (P＜0.05), but there was no significant difference in specificity (80.00%, 20.00%) (P＞0.05), single factor analysis showed that proportion of patients older than 60 years old in study group was significantly higher than control group, SBP, DBP, blood sugar, NIHSS scores in observation group were significantly higher than control group (P ＜0.05); multiple factor Logistic regression analysis showed that area of cerebral infarction, blood sugar level, NIHSS scores, CT low density change were independent risk factors of occurrence of hemorrhagic transformation after cerebral infarction. Conclusion Enhanced CT scan can improve diagnostic efficacy to hemorrhagic transformation after cerebral infarction, blood sugar level, NIHSS scores, CT low density change are independent risk factors, it should be paid attention.