Semisolid alloy slurry was prepared by an efficient and energy-saving technology which consists of low superheat pouring and slightly electromagnetic stirring (LSPSES). The effects of the main preparing parameters on the slurry were researched. The results indicate that the slurry to satisfy rhoe-forming needed can be prepared by LSPSES. The pouring temperature and the stirring power remarkablely affect the morphology and size of primary α-Al in semisolid Al alloy slurry. Through the suitable slightly electromagnetic stirring, the pouring temperature can be suitably raised to reach the efficient and energy-saving effectiveness.