Abstract: The Pangkaimen gold deposit is located in the Aihui-Huma gold metallogenic belt in the northeastern Great Xing'an Range, and is an epithermal gold deposit controlled by the Late Jurassic-Early Cretaceous Guliku-Huma volcanic fault basin. Diorite encountered by deep drilling in the mining area holds significant indicative meaning for the metallogenic tectonic setting and the regularity of gold mineralization. The diorite is characterized by enrichment in potassium (w(K2 O) = 4.06 %–4.25 %), iron (w(FeO) = 2.45 %–2.65 %, w(TFe2 O3) = 6.41 %–6.50 %), and magnesium (w(MgO) = 3.33 %–3.54 %), while being relatively poor in alkali. It exhibits high contents of Sr and Y (619×10-6–687×10-6 and 28.6×10-6–29.3×10-6, respectively), with low w(Sr)/w(Y) (21.33–24.00) and (La/Yb)N (11.11–11.65) ratios, indicating geochemical features typical of island arc magmatic rocks. Trace element and rare earth element characteristics show significant REE fractionation, weak negative Eu anomalies, and relative depictions in Nb, Sr, P, and Ti. Zircon U-Pb dating yields a crystallization age of 111.1 Ma ± 1.6 Ma for the diorite, which also contains abundant captured zircons of Mesoproterozoic, Neoproterozoic, and Paleoproterozoic ages. The diorite possesses an active continental margin affinity. Its geochemical features indicate a magmatic process involving hornblende fractional crystallization and slab dehydration, while also suggesting magma source characteristics related to subduction or crustal contamination, likely associated with the delamination of a subducted slab. Hf isotopic compositions reveal heterogeneous εHf(t) values for the diorite, similarly indicating the involvement of both juvenile and ancient crustal materials in the magma source. The diorite formed in a regional extensional regime during the late Early Cretaceous, under a geodynamic background influenced by the subduction of the Paleo-Pacific Plate and slab delamination. Regionally, the diorite is closely associated with gold mineralization, likely serving as an important conduit and carrier for the migration of deep-seated metallogenic materials and the extraction of ore-forming elements from the surrounding rocks.