Effects of extruded process, such as extruded temperature and cooling rate, and deformation rate on microstructure and properties of AZ31 magnesium alloy were investigated to optimize processing parameters. The results indicate that the mechanical properties and microstructure of the AZ31 magnesium alloy are relavant with to extruded temperature, deformation rate and cooling rate. Twin-crystal periodically exists in the structure of the AZ31 alloy during extrusion process, and it is helpful for the creation of twin-crystal in the structure with low extruded temperature and deformation rate as well as high cooling rate. Extruded force is decreased with increasing in extruded temperature, and the strength of the alloy can be improved with rising deformation rate in case of water cooling. Meanwhile, slight effects of varied extrusion parameters on electronic conductivity can be observed. The tensile strength and electronic conductivity of the alloy are 272.2 MPa and 17.3 MS/m, respectively, with extruding at 400 ℃ and extruding rate of 14.5 in the condition of water cooling .