Abstract: The north part of Henan Province is located geologically in the south part of the North China platform,no lower Ordovician fossil was collected in last decades.Recenty,the authors found the lower Ordovician conodonts from Linxian County,thus providing the basis for determation,subdivision and correlation of lower Ordovician in this area. Based on the abundant eonodonts,Yeli and Liangjiaohan Formations can be divided,and“Acodus”oneotensis-Scolopodus restrictus zone in Yeli Formation and Paraserratognathus paltodiformis zone in Liangjiashan Formation can be established in this area. Acorrding to the first discovery of a conglomorate bed in the base of Liangjiashan Formation and the lacuna of several Lower Ordovician conodont zones of North China,a sedimentary hiatus can be determented in this area.