Magnesium is one of the lightest structural metals, increasing its strength is always considered. In the present study, Mg-6%Si alloy was casted using the stir casting process at three temperatures of 790, 770, and 750 degrees Celsius in a semi-solid state, and then the melt was subjected to a pressure of 110 MPa until complete solidification. Also, in order to compare the results and observe the effects of semi-solid casting conditions, a sample was cast without stirring and at temperature of 800 degrees Celsius. The microstructure, compressive strength, hardness and wear resistance of the samples were determined and evaluated. The results of the microstructure analysis showed that semi-solid casting leads to a change in the microstructure from dendritic to spherical; The best conditions were related to the sample with casting temperature of 770°C, in this sample the dendritic structure was almost eliminated and a quasi-spherical structure was created. The results showed that in the optimal sample, the compressive strength and hardness increased by 17.5 and 42%, respectively, and the friction coefficient decreased by 7% in comparison with the sample which was casted in non-semi-solid state.