Objective To study the impact of human urinary kallidinogenase (HUK) on collateral circulation and blood perfusion in patients with acute cerebral ischemia (ACI) using multi-modality CT methods. Methods In a randomized controlled clinical trial, 75 patients diagnosed with ACI were enrolled and divided into experiment group (treated with HUK)and control group (untreated with HUK). All participants underwent computer technology perfusion (CTP) and computed tomographic angiography (CTA) examination before and fourteenth day after treatment. The CT cerebral perfusion imaging (CTP), CT cerebrovascular imaging (CTA) and National Institutes of Health Stroke Scale (NIHSS) score were analyzed in two groups. The NIHSS score, cerebral blood flow (CBF), cerebral blood volume (CBV), mean transit time (MTT), and time to peak (TTP) were compared between the two groups before and after 14 days therapy. Results ① After treatment, The two group showed increased CBF and CBV values and decreased MTT and TTP values. The CBF improvement was significantly better in the HUK-treated group than in the control group (t=2.470,P<0.05).②MTT and TTP were shorter in the HUK-treated group than in the control group (t=2.126, t=2.213, P<0.05).③ CTA maximum intensity projection (MIP) sequence revealed that the number of patients collateral vessels was significantly increased in the HUK-treated group than in the control group ( x2=4.265, P<0.05). ④The NIHSS score improvement was significantly better in the HUK-treated group after 14 days treatment than in the control group (t=4.330, P<0.05). Conclusion Human urinary kallidinogenase can improve blood perfusion and ameliorates neurological deficits. It is a safe and effective drug for treating ACI patients. The multi-modality CT methods are effective measure to assess blood perfusion and collateral circulation in patients with acute cerebral ischemia.