Mesoproterozoic quartz diorite was discovered for the first time in the Solonker area, Urad Zhong Qi, Inner Mongolia. The quartz diorite is rich in Mg, alkali (especially Na), and Ca, and poor in Si and Ti, suggesting it should belong to alkaline rocks series. The rock is enriched in LREE and depleted in HREE and shows no obvious Eu anomaly. Trace elements analysis shows that the rocks are rich in LILE (Rb, Ba and Sr) and poor in HFSE (Nb, Ta, Zr, Hf and Ti), indicating the signature of arc magma related plate subduction. The diorite probably formed in a volcanic arc setting, with magma deriving from partial melting of the mantle wedge metasomatized by subducted slab- released fluids/melts and source rocks likely being metabasaltic and metatonalite rocks. LA- ICP- MS zircon U- Pb dating yields a weighted 207Pb/206Pb average age of 1410±11 Ma, which likely represents the crystallization age of the quartz diorite. Combined with the regional tectonic setting, this study concludes that the northern and northwestern margins of North China Plate experienced the convergence of plate subduction at least at 1410 Ma, indicating that the quartz diorite was the direct product of the plate subduction. The results in this study provide new evidence for the start time of northward subduction convergence of the northern margin of North China Plate and are the important basis for tectonic evolution of northern North China in the Mesoproterozoic.