An unilateral and isothermal compression experiment on semi-solid AZ61 fabricated by stain-induced melt activation（SIMA）process were carried out by using the Gleedle-1500 dynamic material testing machine

and the mechanical behavior of semi-solid AZ61 at the high solid fraction was researched

and the relationships among process parameters（strain rateε’

temperatureθ（solid fraction fS）） with stress were studied.true stress-strain relation curve are obtained in the experiment above

and the meanings of mechanical behavior and thixotropic strength are analysed.the results show that the thixotropic strength exists when the solid fraction in semi-solid AZ61 material is relatively high and they jointed with each other to constitute the solid skeletons

and the thixotropic strength is decreased with increase of the heating temperature and decreasing of the strain rate.