Numerous mafic microgranular enclaves (MMEs) with different shapes are found in quartz monzonites of the Muchen pluton in Zhejiang Province. Precise LA-ICP-MS U-Pb dating was conducted on zircon grains extracted from the host quartz monzonites and the MMEs, yielding crystallization ages of 112.1±1.0Ma and 112.4±1.2Ma, respectively. The consistent ages within analytical errors suggest that the host rocks and MMEs were coeval, providing crucial evidence for magma mixing during their petrogenesis. The MMEs commonly show plastic forms and contain similar Kfeldspar megacrysts to the host rocks. Furthermore, plagioclases with corerim zoning texture and apatites with euhedral acicular shape occur widely in the MMEs. These micrographic features are also consistent with the involvement of magma mixing in their petrogenesis. The MMEs and host quartz monzonites show similar zircon Hf isotopic signatures with εHf(t) values ranging from negative to positive. Integrated geological and geochemical characteristics suggest that the MMEs in Muchen pluton were most likely produced by magma mixing between mafic magmas derived from a depleted mantle source and induced felsic magmas generated from partial melting of crust materials.