The compositions of (titano)magnetite in magmatic and hydrothermal ore deposits have shown the potential to discriminate mineral deposit types. However, primary Fe-Ti oxides were sometimes overprinted by metamorphic event(s) over the long geologic history. To what extent the Fe-Ti oxide aggregates in mafic rocks can be modified, either by re-equilibration or interaction with the silicates, during high-grade metamorphism has not been systematically studied so far. The Mianhuadi mafic complex intruded at similar to 260 Ma as a layered intrusion in the Emeishan large igneous province, SW China has undergone granulite-facies metamorphism in Eocene during the development of the Ailao Shan-Red River shear zone. The primary igneous titanomagnetite underwent oxyexsolution and reacted with the silicates to form magnetite, ilmenite and pleonaste, resulting in an increased volume proportion of ilmenite and pleonaste. A retrograde chlorite + carbonate assemblage was found to replace the magnetite whereas AlO(OH) sometimes replaced pleonaste. Redistribution of elements associated with the oxyexsolution occurred that trace elements with larger partition coefficients in magnetite (e.g. Al, Ga, V and Cr) than in ilmenite are more enriched in magnetite after metamorphism and vice versa. Iron-Ti oxide equilibrium calculations indicate that the increased oxygen fugacity is mainly responsible for the oxyexsolution of ilmenite and therefore the geochemical variation of magnetite. Metamorphic magnetite from the Mianhuadi mafic complex can be clearly distinguished from its magmatic precursor by high Ga/Zr and V/Ti ratios. We further propose that V versus Fe/Ti diagram can be used to discriminate between magmatic, metamorphic, and metasomatised (titano)magnetite.