Objective: To explore the mechanism of multi-infarct dementia (MID) treated with the principle of Yijing Tishen (YJTS, reinforcing Kidney-essence and refreshing mental activities). Methods: MID rat models were established successfully with injecting sterile and naturally dried blood clots of the homologous rat into common carotid artery and screened by the first jumping-off latency of diving-platform reflex, based on which, the effect of YJTS in learning and memorizing, monoamine neurotransmitters content in brain tissue, malondialdehyde (MDA) content and superoxide dismutase (SOD) activity in serum and brain tissue, and brain morphosis of multi-infarct rats were observed. Results: Obvious malfunction of learning and memorizing was found in MID rat models, and there were also significant decreasing of monoamine neurotransmitters content in partial brain zones, decreasing of SOD activity in brain and increasing of MDA content in serum and brain. YJTS could obviously improve learning and memorizing, raise SOD activity and monoamine neurotransmitters content in brain tissue, lower MDA content in serum and brain of MID rat models, protect brain morphosis of multi-infarct rats. Conclusion: YJTS might treat MID by restraining lipid peroxidation, improving monoamine neurotransmitters content in partial brain zones and decreasing ischemic damage of brain tissue. Objective: To explore the mechanism of multi-infarct dementia (MID) treated with the principle of Yijing Tishen (YJTS, reinforcing Kidney-essence and refreshing mental activities). Methods: MID rat models were established successfully with injecting sterile and naturally dried blood clots of the homologous rat into common carotid artery and screened by the first jumping-off latency of diving-platform reflex, based on which, the effect of YJTS in learning and memorizing, monoamine neurotransmitters content in brain tissue, malondialdehyde (MDA) content and superoxide Results: Obvious malfunction of learning and memorizing was found in MID rat models, and there were also significantly decreased of monoamine neurotransmitters content in partial brain zones, decreased of SOD activity in brain and increasing of MDA content in serum and brain. YJTS could obviously improve learning and memorizing, raise SOD activity and monoamine neurotransmitters content in brain tissue, lower MDA content in serum and brain of MID rat models, protect brain morphosis of multi-infarct rats. Conclusion: YJTS might treat MID by restraining lipid peroxidation, improving monoamine neurotransmitters content in partial brain zones and decreased ischemic damage of brain tissue.