Abstract: The dynamic Vickers hardness of as-extruded Mg-10Gd-3Y alloy is investigated and the microstructure around the indentation is analyzed.The results show that the dynamic Vickers hardness of as-extruded Mg-10Gd-3Y alloy is higher than the corresponding static ones,and is stress rate sensitivie.The dynamic Vickers hardness increases and reaches maximum with increasing strain rate.There is the twin and deformation around the indentation region,and the number of twin reduces with increasing strain rate.