Abstract: With the method of U-Pb isotope dating of detriatal zircon from Middle Jurassic Mohe Formation, the authors detected that detrital zircon ages are clustered in the range of 1425-170 Ma, which suggests that the basement of Mohe Basin has complex provenance. The provenance of Mohe Basin is mainly made up of Mesoproterozoic metamorphic volcanic rocks with the detrital zircon age of 1425-1064 Ma, Neoproterozoic metamorphic intrusive rock with the detrital zircon age of 888-550 Ma, Cambrian-Ordovician metamorphic supracrustal rock and metamorphosed plutonic intrusive rock with the detrital zircon age of 517-441 Ma, Permian-Carboniferous intrusive rock with the age of 327-252 Ma, and Triassic and Middle Jurassic intrusive rock with the age of 250-170 Ma. These data correspond?to the ages of geological bodies on the south margin of the basin, which shows that the source of the basin was from the Middle Proteronic -Middle Jurassic geologic body in the south, with the youngest age of detrital zircon being 17 Ma. It is therefore held that the lower sedimentary limit of the Mohe Formation is not earlier than early Middle Jurassic. The results achieved by the authors provide new evidence for the study of the evolution of Mohe Basin