Semi-solid casting-rolling for magnesium alloy has been conducted on a self-developed semi-solid casting-roller. The results show that the casting-rolling has greatly affected the microstructure of the semi-solid magnesium alloy. Primary phase in the semi-solid magnesium alloy is converted into spheroidized structure from irregular dendrite structure after casting-rolling. The spheroidized role of casting-rolling process is possible attributed to eliminating sharp angle by friction and flow between solid state and liquid state or coalescence of rotation and collapse of solid particle. In addition

microstructures of the semi-solid casting-rolling exhibits different characteristics at different processing conditions in surface and heart. The microstructure of thick plate is characterized by chilling fine equiaxed area on surface and semi-solid structure in heart while for thin plate

it is characterized by uniformly distributed structure.