Huperzine A is extracted from Chinese medicinal plants of the genus Huperzia qiancengta in natural plant alkaloid, is a potent, reversible and selective second generation of acetylcholinesterase inhibitor, the appearance of a slightly yellow or white crystalline powder, soluble in chloroform, soluble in methanol, ethanol, slightly soluble in water, has a high fat soluble, small molecules can easily penetrate the blood-brain barrier, enters the central mostly distributed in the brain's frontal, temporal lobe, hippocampus and other brain areas associated with learning and memory, in a low dose of acetylcholinesterase (AchE) has a strong inhibitory effect, the distribution of synapses the clearance of acetylcholine (Ach) content increased, thereby enhancing neuronal excitability conduction, strengthen the excitatory effect of learning and memory of brain regions, to improve cognitive function, enhance memory retention and promote memory for reproduction Use. Is the most successful treatment of Alzheimer's disease (Alzheimer's disease) in china.