The recently discovered Jidetun deposit is a large molybdenum deposit，located in the metallogenic belt of Lesser Xing’an–Zhangguangcai Range in the northeast China. We investigated the quartz monzonite in the Jidetun deposit by integrating geochemical analysis，in situ zircon U-Pb dating and Hf isotopic analysis for the first time. Fifteen zircons of JDT-N sample yield excellent concordant results with a weighted mean 206Pb/238U age of 160.48 ± 0.82 Ma （n = 15，MSWD = 0.32）. On the basis of precise isotope ages data，rock-forming and mineralization ages of Jidetun porphyry Mo depositwere determined as the Middle Jurassic （170.9 ~ 160.5 Ma）. Jidetun quartz monzonite is a metaluminous I-type granite and belongs to the high-K calc-alkaline series in category. Their SiO2 and Al2O3 content of quartz monzonite are 67.72％ ~ 70.84％and 14.26％ ~ 15.68％，respectively. The alkali （K2O + Na2O） content ranges from 7.23％ to 7.95％，with K2O/Na2O ratios from 0.72 to 0.97. Its aluminum index （A/CNK） is 0.97 ~ 0.98. The quartz monzonite is also characterized by intense fractionation between LREE and HREE （LaN/YbN = 6.39 ~ 32.34），with weak negative Eu anomalies （δEu = 0.68 ~ 0.9）. The trace element analyses show clear fractionation between HFSE and LILE，and the quartz monzonite are strongly enriched in Rb，Th，U and K but depleted in Nb，Ta，P and Ti. The Hf isotope indicates that all of the εHf（t） values of the Jidetun quartz monzonite lie between 4.02 ~ 9.11，with a mean of 7.1. The two-stage Hf model ages （TDM2） are in the range of 625 ~ 950 Ma，which manifests that they are derived from the juvenile lower crust materials originating from the Neoproterozoic depleted mantle. Based on the data of geochemistry，precise isotope ages and tectonic evolution，we infer that the formation of the Jidetun porphyry Mo deposit is closely associated with the subduction of the Paleo-Pacific Plate.