Alzheimer's disease (AD) is a genetically complex disorder, and the pathophysiological process of AD is thought to begin many years before the diagnosis of AD dementia. This long pre-dementia phase of AD would provide a critical opportunity for therapeutic intervention. Therefore, pre-dementia stage of AD, including mild cognitive impairment (MCI) and pre-MCI, have attracted great interest and become a focus of the research for AD．Many genes have been reported to contribute to the disease susceptibility. So far, the apolipoprotein E gene (APOE) ε4 allele is considered as an only undisputed genetic risk factor for sporadic AD (SAD). A large number of studies aimed to help uncover the remaining disease-related loci in recent decades, but the genetic researches associated with conversion of pre-MCI, MCI to AD dementia are still rare. Here we provide a review on some main AD candidate genes.