Objective: To study the clinical efficacy of carotid artery injection of ligustrazine phosphate injection for treatment of cerebral infarction. Method: Two-hunrend and fourty patients (45 to 65 years) surffered from cerebal infarction were randomized into treatment group (120 cases) and control group (120 cases). Treatment group was taken with the convientional treatment supplemented with carotid artery injection of ligustrazine phosphate, and the control group was only taken convientional treatment supplemented with vein injection of ligustrazine phosphate. Two groups were observed with integrated effects, neurological deficit score, area of cerebral infarction etc, before and after treatment. Result: The total effective rate of carotid artery injection was 94.2% (113/120). The total effective rate of the control group was 85.8% (103/120). No case with adverse reactions was found in treatment group. The neurological deficit score and area of cerebral infarction in the treatment group was better than that in the control group (P<0.05). The shorter the disease history, the better the treatment showed. Conclusion: Carotid artery injection of phosphate ligustrazine can reduce neurological deficit score and area of cerebral infarction.