Abstract: The semisolid A356-Ce alloy slurry was manufactured by low superheat pouring, and the effects of Ce addition on the morphology and the size of the primary phase in the semisolid A356 alloy were researched. The results indicated that semisolid A356 alloy contained certain Ce addition with particle-like and rosette-like primary phases could be prepared by low superheat pouring. The isothermal temperature of A356 melt will affect the refining effectiveness of Ce addition on the primary phase in the alloy. The refining mechanism of Ce on the primary phase in semisolid A356 alloy can be concerned with the eutectic reaction induced by Ce in the alloy.