1. College of Earth Sciences，Jilin University，Changchun 130061，China; 2. Applied Technology College，Jilin University，Changchun 130012，China; 3. Institute of Geologic Survey of Jilin Province，Changchun 130061，China; 4. Inner Mongolia Chifeng Geology and Mineral Resources Exploration Development Institute，Chifeng 024000， Inner Mongolia，China

In order to determine the geochronology，petrogenesis and tectonic background of Mingyuegou For- mation volcanic rocks in Yanbian area，the research of petrology，SIMS zircon U- -Pb geochronology，geochemistry and zircon Hf isotopic have been taken． The results show that the zircons from the andesite rocks are magma genesis zircons，and the zircon 206 Pb/ 238 U dating were (111 ±4) Ma (n =6，MSWD =3. 2) and (113 ±3) Ma (n =6， MSWD =1. 4)，belonging to the later Early Cretaceous． The geochemical data show that the andesite rocks belong to high- k calc- alkaline series，enriched in LILE (K，Ba) and LREE，relatively depleted in HREE and HFSE (such as Ta，Nb)． Combined with Hf isotopes，it is showed the primary magmas of the andesite rocks of the Mingyuegou Formation were from the depleted mantle affected by subducted slab fluids． Combined with the research of regional tectonics，the formation of andesite rocks may be closely related to the subduction of Paleo - - Pacific plate towards Eursia a plate．