Large-scale Early Paleozoic intermediate-felsic granitic plutons are distributed at Kaladawan in the middle-eastern segment of North Altyn, and provide important evidence for understanding early Paleozoic tectonic-magmatic activities and regional tectonic evolution in North Altyn. In this paper, the monzogranite exposed in southern Kaladawan was analyzed using zircon SHRIMP U-Pb dating, wholerock geochemistry and Hf isotopes. Zircon SHRIMP U-Pb dating yields an age of 484.2 ± 4.9 Ma (MSDW = 0.46) for the monzogranite, suggesting its emplacement in Early Ordovician. The monzogranite is geochemically characterized by high K2O (365%~476%) and alkali (Na2O+K2O=831%~866%), low MgO (06%~09%), P2O5 (006%~011%), TiO2 (039%~ 058%) and FeOT (1.82%~2.34%), with A/CNK values ranging from 0.96 to 1.01, suggesting that it can be classified as the high K calcalkaline and metaluminusweak peraluminous Itype granite. The primitive mantle normalized trace element patterns and chondritenormalized REE diagrams of monzogranite show obvious enrichment in LILEs (such as K, Rb, Ba, Th, U) and LREE, depletion in HFSEs (such as Ti, Ta, Nb, P) and HREE, with slight positive Eu anomalies, revealing the arc magma affinity. Insitu zircon Hf isotope data display that the monzogranite has depleted Hf isotopic compositions with positive εHf(t) values (+4.08 to +8.26) and young tDM2 (875~1099 Ma), reflecting that mantlederived juvenile crust plays a significant role in the magmatic process. Together with the tectonic regime of the monzogranite and previously published data, we suggest that the monzogranite probably formed in an active continentalarc setting related to southward subduction of the North Altyn Ocean during the Early Paleozoic. The magma likely originated from partial melting of hybrid crust consisting of mantlederived juvenile crust and ancient continental crust, suggesting that the rock experienced mixing of crustal and mantle magma. These features of the monzogranite are consistent with that of the Early Paleozoic arctype magmatic rocks in North Qilian. Therefore, our research provides new evidence that North Altyn was the western extensional part of the North Qilian.