Objective:To study the formula of Dingzhi Xiaowan

and discuss the best proportion of four chinese medicines which compose it.Methods:Detect the ability of learning

memory and the energy of acetylcholine esterase (AchE) of the mice which were treated with different solutions prepared according to the orthogonal layout.Results & Conclusion:The effects of the formula composed of all four chinese medicines are better than others.Among the four Chinese medicines

Radix Ginseng presented the most significant effects on improving the ability of learning and memory in model mice

whereas Radix Polygalae

Rhizoma Acori Tatarinowii and Poria exhibited the attenuated properties in turn.This study showed that the best proportion of four Chinese medicines should be 3∶2∶0.6∶3 and indicated that the traditional proportion was reasonable.