Abstract: In order to study the effect of squeeze casting pressure on the structure and properties of mechanical shell AZ80 magnesium alloy, squeeze casting tests of AZ80 magnesium alloy samples for mechanical shell were carried out with different squeeze casting pressure under the condition that the pouring temperature of 690 ℃, extrusion speed of 210 mm/min, holding time of 250 s and die preheating temperature of 300 ℃ were unchanged, moreover, the microstructure of the samples was observed and analyzed, the mechanical properties and wear resistance of AZ80 magnesium alloy specimens at room temperature were tested and compared. The results show that with the increase of the squeeze casting pressure from 8 MPa to 28 MPa, the microstructure of AZ80 magnesium alloy specimens is refined firstly and then coarsened, and the mechanical properties and wear resistance firstly increase then decrease. When the squeeze casting pressure is 8 MPa, the tensile strength and yield strength of the sample are the minimum and the wear volume is the maximum, which are 325 MPa, 257 MPa and 45.6×10^-3mm³, respectively. When the squeeze casting pressure is 24 MPa,the tensile strength and yield strength of the sample are both maximum and the wear volume is minimum, which are 386 MPa, 299 MPa and 31.7 ×10^-3mm³, respectively. The squeeze casting pressure of AZ80 magnesium alloy sample of mechanical shell is preferably 24 MPa.