Microfossils discovered first in the Xuanlong--type iron formation in north-western Hebei are described in the paper. They are well preserved in the basiclaminae of iron stromatolites ("kedney hematite") and the concentric laminae ofiron oncolites ("oolitic hematite") in the lower part of the Chuanlinggou Forma-tion of the Changcheng System. The microfossils include filamentous and partlyspheroidal forms and form stromatolite--building mats. There are three genera ofmicrofossils, which may be classified as Oscillatoriaceae and Chroococcaceae ofprocaryote Cyanophyta. The isotopic age of the fossil--bearing horizon is about1800--1757 Ma. They show obvious differences from and some similarities to themicroflora from the Gunflint Formation of North America. The discovery of the microfossils is of important significance in enriching bio-logical categories in iron formations. studying the origin of iron and indicatingsedimentary environments and stratigraphical correlation.