Abstract: There are a series of ancient oceanic crust relics along the fracture belt between the Archean granulite belt and the Paleoproterozoic Hongqiyingzi group in the North Hebei Province. Recently we have found widespread Nb-enriched basalt (Nb > 7×10-6 and Nb/Th+Nb/La > 0.6 ) in this area, which is very rare in other regions. The discovery will provide powerful proof for distinguishing ancient oceanic crust and will also supply important information for the Precambrian geological and tectonic evolution.