In order to study the possible formation mechanism of MME in the Jingde pluton. Mineral chemical analyses of granodiorite and biotite in the MME were conducted to qualify the magma crystallization conditions and establish the diagenetic link between the MME and host granodiorite.Methods: Combined with field work and microscope observation, using EPMA and LA- ICP- MS analysis of biotite and plagioclase to constrain the origin of MME.Results and conclusion:(1) In the Jingde pluton granodiorite and MME formed at analogous temperatures (824~864 ℃, 802~828 ℃), pressures (0.354~0.787 GPa, 0.279~0.353 GPa) and oxygen fugacity (-13.4~-12.7, -12.8~-11.2), respectively.(2)The compositions of biotite and plagioclase in the Jingde pluton MME are comparable to that of the host granodiorite, indicating that MME is not of crust—mantle mixing origin, but a cognate magmatic evolutionary relationships.(3)The enriched mantle was partially melted induced by the subduction of the Paleo- Pacific plate and formed basaltic magma. The underplated basaltic magma evolved to intermediate melt by differentiation. Early low-evolving magma is the magma chamber cooled first by upward introsions due to lower viscosity, followed by a large-scale upward intrusion of highly evolved granodiorite magma. The cooled semi- plasticized intermediate rocks in the magma channel were dragged and wrapped to form MMEs in the granodiorite.