The microstructure and mechanical properties of AZ61-1Sm-xSb alloy were investigated. The results shown that the mainly phase of AZ61-1Sm-xSb alloy were β-Mg17Al12, Al2Sm, Al3Sm and SbSm. Compared with AZ61, the shape of Mg17Al12 in AZ61-1Sm alloy are discontinuous; Due to the addition of Sm and Sb, the microstructure is further refined, and a new SmSb phase is formed. Addition of Sm and Sb enhanced the strength of hot-extruded and T5 AZ61 alloys at room temperature. Moreover adding Sb into AZ61-1Sm alloy could enhance its strength at 150℃ obviously.