Abstract: The Bayan Bold gold deposit is situated in the obduction zone of platform margin to the north of Inner Mongolian suture zone. Study on petrology, geochemistry and isotope chronology shows that the metallogenesis is closely related to granite-porphyry, which belongs to the Early Ordovician adakite formed in volcanic arc. The ore-forming fluid is derived from magma activity, with rich CO₂ and alkali materials, in a weak reduction and medium-high temperature environment. The Bayan Bold gold deposit is of porphyry-type related to adakite.