The Cathaysia flora, one of the most prominent floras of the Carboniferous and Permian, was mainly distributed in East Asia and was characterized by numerous endemic elements. China is one of the most important localities of the Cathaysia flora and it is also the center of origin of this flora. This paper reviews and discusses the characteristics of the Cathaysia flora and the biogeographically mixed Permian Cathaysian-Angaran floras of East Asia. In addition, the formative mechanism of the mixed Permian floras is also discussed.