The Honghuapu intrusions, located in the western segment of northern Qinling orogenic belt and intruding into Ordovician Caotangou Formation, are medium-fine grained trondhjemites. Geochemical studies indicate that they are weakly peraluminous calc-alkaline rocks and can be classified as I type granite. Light REE elements are rich, and light and heavy REE are not significantly fractionated. In chondrite-normalized REE diagrams, all samples are LREE-enriched with insignificant Eu anomalies. Their major and trace element geochemical characteristics are all comparable with features of typical volcanic-arc granites. It is thus concluded that the Honghuapu intrusions were formed in island arc settings. The Honghuapu intrusions were dated at (450.5±1.8)Ma by the LA-ICPMS U-Pb zircon method. The new geochemical dating has important significance to the study of Early Paleozoic tectonic evolution and dynamic mechanism of Qinling orogenic belt.