As a key microcontinental block/terrane in the southernmost Central Asian Orogenic Belt (CAOB), the genesis of early Paleozoic magmatism and tectonic evolution for the Dunhuang Block still remain poorly constrained, thus limiting the whole understanding of ocean-continental subduction-accretionary evolution of the southern Paleo-Asian Ocean (PAO) and the recycle of deep magmas materials. Here we have newly identified the Silurian quartz diorite from the Changshaliang area in the eastern Danghe reservoir in the central part of Dunhuang block, NW China. The petrology, zircon U-Pb dating, whole-rock geochemistry, and zircon Hf isotopes data have been carried out on the Changshaliang quartz monzodiorite. Zircon U-Pb dating results reveal that the quartz diorite was formed at ca. 428~426 Ma. Whole-rock analyses show that the quartz monzodiorite is relatively rich sodium (K2O/Na2O = 0.84~0.99), high Al2O3 (16.5~17.0%), Mg# (51.5~53.0) and low A/CNK (0.96~1.00) values, and point to the high potassium calc-alkaline metaluminous series. These samples studied exhibit negative Eu anomaly (Eu/Eu* = 0.70~0.77), enriched in larger ion lithophile elements (e.g., Rb, Ba, and Th), depleted in high field strength elements such as Nb, Ta and Ti, together with the low Y (16.3~19.0 × 10-6) contents and Sr/Y ratios (20.3~24.5), showing typical geochemistry characteristics of arc magma. Zircon Hf isotopes results indicate the Changshaliang quartz monzodiorites have a wide variable and negative εHf(t) value of -12.0 to -2.2, and older two-stage model age ranging from 2136 Ma to 1525 Ma. All the above features suggest that the Changshaliang quartz monzodiorites originated from melting of overlying mantle wedge metasomatized by subduction-related sediment melts, subsequently which triggered remelting of Paleoproterozoic lower crust materials. This study, combined with the existing research results, suggest that the Dunhuang Block was strongly involved in the orogenic events related to the southern part of the CAOB during the early Paleozoic period, which caused the modification and activation of crust, finally resulting in multi-stage magmatism events with different compositions resulted in significant activation crust. The block was at an active continental margin arc environment where the PAO continued to subducted to the Dunhuang Block.