The cerebral blood flow autoregulation (CAR) is the brain blood supply regulation process of brain vessel under the control of nerve. The nerve and physiological states of the brain can be judged through evaluating the CAR. In this paper, using bioimpedance technique to evaluate CAR is studied. The brain blood flow circulating resistance parameter and artery blood vessel elasticity parameter are introduced in the CAR evaluation. In the experiment, the intervene method was used to make the brain blood supply system of the subjects in normal and abnormal states. The brain blood flow impedance signals were measured in the two states, and the resistance parameter and elasticity parameter were extracted. Comparative analysis shows that the change ratios of the resistance and elasticity parameters are 8. 53% and 20. 89% , respectively. Statistical analysis shows that these two parameters have significant difference (P< 0. 001) before and after the intervention. The experiment results verify that the brain blood flow bioimpedance technique can track the change process of CAR, and the proposed method has great significance for the further study of brain physiological activity and brain nerve function using bioimpedance detection.