Alzheimer's disease (AD) has become into a global concern to public health. Since it was first discovered in 1901, people have studied it for more than one hundred years, and many hypotheses have been proposed. However, its pathogenesis has not been completely revealed. In addition, the treatment and diagnosis of AD is a challenge worldwide, especially in low-income countries. Fortunately, however, some classical hypotheses have their validity, such as cholinergic injury hypothesis, Aβ cascade hypothesis and abnormal modification hypothesis of tau protein. And the drugs developed on the basis of these classical hypotheses have finally been proved to have therapeutic effects on Alzheimer's disease through continuous experiments by researchers. Among them, Aricept is a drug used in mild AD treating, which acts as cholinesterase inhibitor, while N-methyl-D-aspartic acid (NMDA) receptor antagonist Namenda is used to treat moderate or severe AD. This review reviews the background of Alzheimer's disease and its two available treatment medicines, called Aricept and Namenda, including drug mechanism, efficacy, safety and their pharmacokinetics.