A brief account is given on a new species of the genus Kaotaia, K. transoersa sp. nov. and some variations in the course of its ontogeny, together with an emphatic discussion on its systematic position, origin and evolutionary tendency. Also described is a new genus Eokaotaia from the stage of Early Cambrian and closely related to Kaotaia, together with its two new species, Eokaotaia gedongensis gen. et sp. nov. and E. longa gen. et sp. nov. These genera and species are of considerable significance in the study on the Classification and evolution of Cambrian ptychopariid trilobites.