Objective To study the effects of low power laser irradiation in nasal cavity on cerebral blood flow and cerebral function in patients with brain infarction. Methods Thirty-nine patients with cerebral infarction were divided into a intravenous laser irradiation group and a laser irradiation in nasal cavity group. For the group of intravenous irradiation (ILIB group,18 cases), the patients lay on the bed with their heads fixed and were treated with intravenous laser irradiation for 30 min. Both before and after the therapy they received a SPECT cerebral perfusion imaging separately. For the group of laser irradiation in nasal cavity (LINC group,21 cases), the patients received laser irradiation in nasal cavity for 30 min and also SPECT cerebral perfusion imaging tests both before and after therapy. BFCR% model was used to quantify the blood flow of the focal and mirror regions. Results SPECT showed that there was significant improvement in perfusion of the entire brain and cerebral function in both ILIB and LINC groups after 30 minutes of treatment,each compared to those before treatment; the changes in the focal rCBF and cerebral function were much more obvious (P0.05). BFCR% in focal region was significantly higher than that in mirror region (P0.05). Conclusion Low power laser irradiation in nasal cavity can improve the focal rCBF and cerebral function of the patients with brain infarction, which is similar to that of the ILIB.