Al₂O₃/Al-10Si composites solidified with different pressures were prepared by hot pressing and high pressure solidification.The effects of high pressure on the microstructure evolution and mechanical properties of Al₂O₃/Al-10Si composites were investigated.The results show that the high pressure solidified Al₂O₃/Al-10Si composite consists of α phase,β phase and Al₂O₃ strengthening phase, and α phase is cell-like.There is a small amount of fine granular β phase with a particle size of about 0.1 μm at α phase grain boundary.The solid solubility of Si in α phase and the microhardness increases with the increasing solidification pressure.The microhardness of the hot pressed sintered material is 55.3 HV.When solidification pressure is 5 GPa,the microhardness is 128 HV and has increased by 133%.The compressive strength has increased from 126 MPa to 702 MPa at 5 GPa.This is due to the high pressure causing an increase in the solid solubility of Si in α phase to form a solid solution strengthening.