Abstract: The Bizigou and Nanhegou copper deposits are located in the southern margin of the Trans-North China Orogen of the North China Craton.They are typical of the Hubi type copper deposits in the Zhongtiao Mountain area of Shanxi Province.Because they are controlled by strata and like stratified, they are also considered as the sediment-hosted stratiform copper deposits.However, the mineralization age of these deposits has not been determined and remain controversial.In this paper, high-precision ⁴⁰Ar-³⁹Ar dating of mica in Bizigou and Nanhegou copper deposits was carried out.The plateau age of Bizigou copper deposit sample was 1825 ± 13 Ma(MSWD=8.86), and the corresponding isochron age was 1820 ± 13 Ma(MSWD=5.67), inverse isochron age of 1820 ± 13 Ma(MSWD =5.63).The samples from Nanhegou copper deposit obtained plateau age of 1861 ± 14 Ma(MSWD=8.17), the corresponding isochron age is 1864 ± 16 Ma(MSWD=8.31), and the inverse isochron age is 1865 ± 16 Ma(MSWD= 8.47).The mineralization ages of the two deposits are consistent within the error range, indicating that the hydrothermal mineralization time of the Hubi type copper deposit is limited to ca.1850 Ma.This age is consistent with the peak metamorphism and retrometamorphism of ca.1.85 Ga in the Trans-North China Orogen.After that, it was found ore bearing quartz veins were developed in the mafic rocks of Zhongtiao Group.⁴⁰Ar-³⁹Ar dating of muscovite associated with sulfide in veins obtained the plateau age of 1851 ± 13 Ma(MSWD= 7.47), the corresponding isochron ages of 1844 ± 19 Ma(MSWD= 7.30)and inverse isochron ages of 1844 ± 19 Ma(MSWD= 7.28), indicating that the mineralization is the product of the same geological event as the hydrothermal mineralization in the mining area.It is proved that metamorphic hydrothermal fluid widely acted on geological bodies throughout the region during the collision orogeny.