The Zhaojinggou Nb-Ta deposit has close relationship with granite. Zircon LA-ICP-MS U-Pb dating indicates that the age of biotite K-feldspar granite in the mining area is 125±1 Ma. Geochemical data show that the Late Palaeozoic magmatic rock is characterized by metaluminous alkaline rock, high potassium and alkali, enrichment of LREE with strong negative Eu anomaly and enrichment of LILE (Rb, Th and U), and strong negative anomalies of Hf and Y in primitive mantle-normalized spidergrams. It thus belongs to A1 subtype of A type granites, and has ¹⁷⁶Hf/¹⁷⁷Hf ratios in the range of 0.000 5~0.003 0, εHf(t) values in the range of -15.42~-5.55 and corresponding model ages (t_DM2) between 2 247 and 1 640 Ma. Granite was formed in a post-orogenic setting, mainly derived from the partial melting of crustal materials.