Four types of lacustrine facies carbonate developed within the Zhuanchengzi section of the Lower Cretaceous Yixian Formation have been recognized in Yixian County of western Liaoning Province. Among them, plenty of chert occurs in brecciated nodular limestone-facies carbonate. The chert can be divided into three types: nodular, lenticular and glaebule based on its configuration, while two types of chert can be defined based on color and transparency. The chert consists mainly of microcrystalline quartz and chalcedony with small amount of calcite and dolomite crystals. The study suggests that the sedimentary environment of carbonates might be relatively-dry, shallow short-lived isolated sags on the floodplain partially accompanied with volcanic activity.