The Linxi fluorite deposits, Inner Mongolia, are mainly hosted in the volcanic-sedimentary stratum and acidic intrusions in the Late Paleozoic-Mesozoic, controlled by the NS and the NNE trending fault zone. The results show that the ESR dating of quartzes from Linxi fluorite deposits ranges from 126.6 to 157.3 Ma, with an average of 137 Ma, indicating that the metallogenic hydrothermal fluid mainly formed in the Late Jurassic-Early Cretaceous. Combined with geological characteristics of deposits and the global fluorite deposits, Linxi fluorite deposits are of hydrothermal origin, and of fracture-filled metasomatic type, which are formed in the conversion period of the middle Yanshanian stage intraplate tectonic regime.