The bojite occurs in the Mangya area, south margin of the Altun Mountains, shows typical calcalkalic series trend. The intrusion is enriched in LREE，LILE ( Rb, Ba, Sr ), U, Pb, and depleted in HFSE ( Nb, Ta, Zr, Hf ), which is similar to the products of islandarc structure setting. Writers considered that the bojite magma originated from lithospheric mantle, the primary magma resulted from partial melting of mantle materials, and mixed with crust materials while the melt uprising. LA-ICP-MS zircon dating shows that the formation age of the bojites is 444.9±1.3 Ma ( WSMD=0.94 ), which suggests that subduction of oceanic crust occurred in southern margin of Altun Mountains in Late Ordovician. So, this paper provides some important evidences for studying further formation and evolution of the Altun Tagh tectonic belt.