This article is for understanding dementia with the perspective of Korean Medicine through research on syndrome differentiations of dementia clinically applied and relations between modern diseases and Korean Medicine pattern types of dementia. clinical papers were searched in China Academic Journals(CAJ) of China National Knowledge Infrastructure(CNKI) from 2012 to 2013. Conclusions are as follows. First, dementia was expressed in many ways such as imbecility, stupidity, fatuity, idiocy, vacuity, etc and was related with amnesia, forgetfulness, speech not in the right order, depressive psychosis(quiet insanity), manic psychosis, depression syndrome. Second, prescriptions such as QiFuYin and ZuoGuiWan from JingYueQuanShu, XiXinTang and ZhiMiTang from BianZhengLu, TongQiaoHuoXueTang, XueFuZhuYuTang and BuYangHaiWuTang from YiLinGaiCuo, HaiShaoDan from YiFangJiJie, HuangLianJieDuTang from WaiTaiMiYao were suggested for dementia. Third, syndrome differentiation pattern types of dementia are kidney deficiency and marrow decrease, qi-blood depletion, liver-kidney depletion, spleen-kidney depletion, heart-spleen deficiency as deficiency patterns and effulgent heart-liver fire, ascendant hyperactivity of liver yang, qi stagnation and blood stasis, phlegm turbidity obstructing orifice, phlegm-blood stasis obstructing orifice, intense heat toxin as excess patterns and qi deficiency with blood stasis, yin deficiency with yang hyperactivity as deficiency-excess complex patterns. Major pattern types are kidney deficiency and marrow decrease, phlegm-blood stasis obstructing orifice, qi stagnation and blood stasis, liver-kidney depletion, phlegm turbidity obstructing orifice.