Abstract: Zircon U-Pb age of granite-porphyry in Hegen Mountain located in the conjunction of the North China plate and the Siberia plate is 137.6±1.6Ma, suggesting that the rockswere formed by magmatic evolution during Early Cretaceous. The geochemical data indicate that major elements are characterized by enrichment of Si, higher DI and NK/A as well as Fe₂O/FeO ratios. The trace element spider diagram indicates that graniteporphyry is relatively rich in Rb, Th, U, slightly enriched in light rare earth elements La, Ce, and depleted in high field strength elements such as Nb, Ba, Sr and Ti, while the distribution model of REE is right oblique, exhibiting relative LREE-enrichment and HREE-depletion, and the HREE curve is flat. These results suggest that the granite porphyry is attributed to high differentiated metaluminous-weakly peraluminous high calc-alkaline series, being typical Ⅰ-type granite. The source materials might have come from crustal felsic rocks with high K and normal water content. The formation of the granite porphyry may be related to the process from the extrusion to extension resulting from the lithosphere thinning after plates collision (including Mongolia-Okhotsk Ocean) with the closure of Paleo-Asian Ocean during the Late Paleozoic to the Early Mesozoic. It was also affected by the westward subduetion of the Paleo-Pacific Ocean.