AlSi30 semi-solid billets were fabricated from AlSi30 alloy powder by using ECAP（equal channel angular pressing）method as a substitute for thermal and cold plastic deformation in the SIMA method（strain induced melt activation）based on orthogonal testing

and effects of processing parameters on microstructure of the semi-solid billets were investigated.The results show that the holding temperature is dominant in controlling grain size and spheroidization rate of primary Si phase

and then holding time

then pressing temperature of equal channel angular.The desirable grain size and spheroidization rate of the primary Si in the semi-solid billets can be observed with holding at 605℃ for 55 min and pressing at 500℃ based on A route.