ObjectiveTo explore the effects of Yiqi Yangyin Huoxue principle on the expression of neurotrophin-3 of the frontal lobe cortex neurons in diabetic rat brain. Methods The diabetic rat model was produced by intraperitoneal injection of streptozotocin(STZ).The Yiqi Yangyin Huoxue drugs was poured into the stomach of the treated group. The brains were taken and the expression of neurotrophin-3 was estimated with immunochemistry 8 weeks later. Results Immunochemistry showed that there were many positive cells in the frontal lobe cortex of the normal group and they were deeply dyed.Positive cells of the model group decreased and their color was shallow .The number and the color of positive cells in the treated group were close to that of the normal group. Conclusion The Yiqi Yangyin Huoxue principle can effectively improve the degenerating of the frontal lobe cortex neurons in diabetic rat brain.