The age of the Ordovician Zhaolaoyu Formation has been determined by fossil assemblage, and different ages have been suggested according to this method. Some researchers thought the Zhaolaoyu Formation was formed during the Late Ordovician according to recognition of the Graptolite zone, whereas others thought it was formed during the Middle Ordovician or late Middle Ordovician according to the Conodont assemblage. In this paper, SHRIMP U Pb zircon age of 453.2 ± 6.9 Ma has been obtained from the volcanic tuff interlayer in the Zhaolaoyu Formation, the Zhaolaoyu section of the Fuping area. Considering the sample was collected under the fossil zone in the Zhaolaoyu section, this age indicated that the Zhaolaoyu Formation developed in the Fuping area belongs to Late Ordovician. Furthermore, the geological implications of this zircon age are discussed in combination with regional data. The form of volcanic tuff interlayer in the Zhaolaoyu Formation may be best interpreted as the responses to the northward subduction of ancient Qinling oceanic basin. The isotope chronological data show that the Zhaolaoyu Formation on southern margin of the Ordos Basin is the youngest in North China Craton, so, these data not only accurately indicate the age of the strata but also have great significance for understanding of the geological evolution of the Early Paleozoic in the whole North China Craton.