Magnesium alloys offer advantages of low density, high specific strength, machinability and availability. So it has been used more and more in many fields, such as automobile, communication etc. In this paper, grain refinement process and SiC nanoparticles reinforcement process are investigated for the purposes of increasing ultimate tensile strengthen and ductility of AM60B magnesium alloys. We find that after grain refinement process the ultimate tensile strength of AM60B alloys with permanent casting increase to 241MPa, which is about 27MPa higher than that of original alloys, and the elongation of it increases up to 20.1%, which is about 8.7% higher than that of original alloys. We added SiC nanoparticle into AM60B alloys in liquid state and found it could increase strength and ductility of alloys. By SiC nanoparticle reinforced process the ultimate tensile strength of magnesium alloys can increase up to 255MPa with the elongation of 19%.