Abstract: The Early Paleozoic magmatites are sporadically distributed in the west of Langshan Mountain of Inner Mongolia, whereas the Late Silurian quartz diorite is mainly exposed in the zone of Hariyinaorui. LA-ICP-MS zircon U-Pb dating shows that the weighted average ²⁰⁶Pb/²³⁸U age of quartz diorite is 419.0±4.0~413.3±1.8Ma. The characteristics of quartz diorite mainly exhibit that the biotite is the main dark mineral, which is characterized by enrichment of TFeO (4.27%~4.65%) and Na₂O (4.17%~4.45%), enrichment of LILE (Sr, K, Pb), depletion of P, Ti and Nb, enrichment of LREE, and depletion of HREE with weak negative Eu anomaly, similar to the characteristics of arc magmatite. La/Ba-La/Nb determinant diagram shows the characteristics of metasomatic mantle, and isotopic characteristics reflect the characteristics of melting of ancient continental crust which has an obvious negative ε_Hf(t) value (-12.1~-8.8) and older T_DM2 value (1981~2362Ma). Tectonic discrimination diagrams and regional geological data show the pluton probably formed the tectonic setting of arc-continent collision. A comparative study of recently published relevant data of Late Silurian quartz diorite in the Bainaimiao area shows that the geochemical characteristics are basically the same, and, therefore, arc-continent collision of Late Silurian extended westward to Langshan area on the northern margin of North China Craton.