Located in North Qinling, the Wuguan intrusive body intruded into the Danfeng Group and developed gneissosity in some regions. It mainly includes diorites and granodiorites and belongs to low-K tholeiitic and medium-K calc-alkaline series, characterized by enrichment of large ion lithophile elements and depletion of high field strength elements, with a high LILE/HFSE ratio. Geochemical data also suggest the involvement of a subduction sedimentary source. All the evidence indicates that the formation of the rock was associated with the ocean subduction. Chondrite-normalized REE patterns show an enriched LREE distribution and a flat HREE distribution, with no obvious negative Eu anomaly. Moreover, the Wuguan intrusive rocks are rich in sodium and aluminum, and have high Sr/Yb and CaO/Na₂O ratios. These geochemical features suggest that these rocks were formed by the remelting of the basaltic rocks with amphibole as a stable residual phase. The result of simu- lation calculation suggests that plagioclase amphibolite produced in an island-arc environment in the Danfeng Group could form the Wuguan intrusive body through partial melting with a degree of 30%～40%. Besides, the residual mineral assemblage is mainly hornblende with a small amount of plagioclase and clinopyroxene, and garnet-bearing residues may be negligible. CL images and LA-ICPMS dating show that zircon U-Pb isotopic age of the Wuguan intrusive body is 438.6±2.2 Ma, and the formation of this intrusive body might be attributed to Caledonian collision event of the North Qinling. This zircon U-Pb isotopic age is later than the period of the subduction of Shangdan Ocean, but the chemical characteristics of this intrusive body are closely related to the island-arc environments. It is therefore inferred that the geochemical characteristics reflected in the Wuguan intrusive body might have inherited some chemical features of its sources in an arc environment. Combined with the REE simulation calculation by the melting of the amphibolites formed in an arc environment, it is proved that the Wuguan intrusive body was formed in a collision orogenic process and it might have been a partial melting product of the pre-existing source in a subduction environment.