Thixo-squeezing and thixo-forging of Mg-Al-Zn alloy semi-solid billets prepared by new SIMA method were carried out.Preparation and thixo-forming characteristics of Mg-Al-Zn alloy semi-solid billets were understood by OM（optical microscope）and tensile testing machine.The results reveal that microstructure of the Mg-Al-Zn alloy can be greatly refined as a result of desirable strain induction effects by equal angular extrusion（ECAE）in new SIMA method

in which average grain size of 20μm can be obtained and which are responsible for the obvious improvement of mechanical properties of the alloy.The spheroidized fine grain with average size of 25μm in the microstructure with uniform distribution of the semi-solid billets can be prepared by ECAE with holding at 560 ℃ for 20 min.Thixo-squeezing and thixo-forging experiment verify that the mechanical properties of the thixo-forming Mg-Al-Zn parts can be improved greatly

and the yield strength

tensile strength and elongation of thixo-squeezed satellite angle frame are 213.1 MPa

312.6 MPa and 15.2%

respectively

while those of thixo-forged magazine plate are 218.6 MPa

320.9 MPa and 14.8%

respectively.