According to the principle that the chronostratigraphic boundary oughtto be a natural boundary reflecting a development stage of the earth

an in-ternational chronostratigraphic system of the Permian has been advanced inthis paper with the complete marine strata of the Permian in PaleotethysRealm as basis and with the development stage of fusulinid

which is thefirst leading fossil group in the Permian

as united indication.In this sys-tem

the Permian is composed of 11 stages of three series

namely(inascending order):the Kasimovian stage(newly defined)

the Gzhelianstage(newly defined)

the Asselian stage

the Sakmarian stage and theXiangzhongian stage of Lower Permian series;the Qixian stage and otherthree stages which remain to be named in future of Middle Permianseries;the Sanyangian stage and the Changxingian stage of Upper Per-mian series.