Abstract: The microstructure, microhardness, tensile and fracture scanning tests of hot extruded AZ80 magnesium alloy sheet were carried out.The microstructure and mechanical properties of the hot extrusion sheet were discussed.The results show that the segregation of the longitudinal structure of the sheet is serious, the difference between the edge structure and the center structure of the plate is great, the longitudinal extension of the center structure of the sheet is large, with strong directivity, but the difference between the transverse structure of the sheet is not obvious.At the same time, the micro-hardness is smaller at the edge of the sheet, but larger in the inside of the sheet, and the thickness is smaller on both sides and larger in the middle, which indicates that the sheet has obvious anisotropy.The longitudinal tensile strength of the sheet is as high as 384 MPa, and the elongation is 10.81%.The microstructure of the sheet fracture shows deep egg dimples inside, which belongs to ductile fracture.