The Larsemann Hills in Prydz Bay represent an important early Palaeozoic ~530 Ma (Pan-African) high-grade tectonic mobile belt of east Antarctica. However, the earlier late-Proterozoic ~1000 Ma (Grenvellian) high-grade metamorphic history of the region is still controversial. A pelitic granulite lens in the region preserves peak assemblage grt-crd-opx-ksp-qtz (M1), and peak garnet grains develop cordierite or crd-opx corona (M2). Quantitative modelling for the Al-rich pelitic granulite via Thermocalc program has been undertaken in the KFMASH model system, suggesting that the peak assemblage was formed by the crossing of the reaction grt+bt+qtz = crd+opx+ksp+melt. The average P-T calculations indicate that M1 peak metamorphic P-T conditions reached ~0.9 GPa and ~900 ℃, while the overprinting M2 assemblage reflects a decompression-cooling path with peak P-T conditions of ~0.7 GPa and 800~850 ℃. Combined with available geochronological data and field relationships, the peak M1 metamorphic assemblage preserved in the Al-rich pelitic granulite is considered to be associated with the late-Proterozoic (~1000 Ma) Grenvellian compressional tectonic D1 event, whereas the overprinted M2 assemblages and M3 myrmeckites may have formed during the early Palaeozoic (~530 Ma) Pan-African high-grade transpressional tectonic D2-D3 events, which led to the development of planar high- and low-strain zones and the intrusion of the Progress Granite and pegmatites in the region.