The magmatic activity products of Indosinian period are exposed sporadically in eastern Qinling orogen belt of Henan Province. Zhifang—Huangzhuang (ZH)area of Songxian County is one of Indosinian magmatic atcivity occurrence in eastern Qinling area. In this paper, the U-Pb zircon age and Hf isotopes of the Mogou syenite, the biggest igneous bodies in Zhifang—Huangzhuang area, have been tested by Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS). The zircons 206Pb/238U concordia age of the Mogou syenite is 245.5±8.0 Ma (95% confidence, MSWD=2.6), which has recorded the alkaline magmatism event during the Early Triassic of the Indosinian period in the Qinling orogen belt. The εHf (t) values of zircons from the Mogou syenite range from -31.89 to -10.59, which gathered at two intervals of -31.89 to -27.64 and -21.02 to -10.59. The Hf model ages of tMD2 are from 1937 Ma to 3267Ma, which formed two age ranges of 1937 Ma to 2591Ma and 3003Ma to 3267Ma. These zircon Hf isotope results have indicated that the Mogou syenite was the mixture of mantle derived alkaline magmas and granitic melts formed by partial melting of lower crustal material, such as gneiss of the Taihua Group, which coincided with the existence of mafic microgranuclar enclaves (MME) in the Mogou syenite. The formation time of the Mogou syenite is in the period of face contact type collision of the Qinling orogen belt, the lithosphere thickness of ZH area increased remarkably in the vertical direction on the effect of the long term continuous collision, and its gravitational instability strengthened. The local small scale lithosphere delamination in ZH area took palce in early Indosinian. Large deep fluids must be discharged while lithosphere delamination of ZH area took place, which suggests that it is ZH area that has huge metallogenic potential, especially in the rare metal elements, such Rb, Zr, light rare earth elements (LREE) and insoluble potash resources related to syenite intrusive itself.