The semisolid slurry of A356 Al alloy was preparation by low superheat pouring and weak traveling-wave electromagnetic stirring. The effects of pouring temperature and stirring power on the semisolid slurry were researched. The results show that the shape of primary α-Al experiences a transition from rosette-like grains to spherical grains with the pouring temperature lowing gradually, and the smaller grains with a spherical appearance distribute in the microstructure homogeneously. The appropriately raising the electromagnetic stirring power is good for the formation of the semisolid A356 Al alloy slurry with spherical microstructure. On the condition of weak traveling-wave electromagnetic stirring, the pouring temperature with low superheat can be suitably raised to reach the effectiveness obtained from the lower pouring temperature without stirring. Therefore the pouring operation is simple and convenient.