The semisolid AlSi7Mg alloy slurry with large capacity was prepared by low superheat pouring and week traveling-wave electromagnetic stirring.The effects of electromagnetic stirring power and frequency on the shape and distribution of primary α-Al grains in the AlSi7Mg alloy slurry were discussed.The experimental results show that the AlSi7Mg alloy slurry with fine and spherical primary α-Al grains distributed homogeneously can be obtained.Under the condition of low superheat pouring and week traveling-wave electromagnetic stirring,when the pouring temperature is 630°C,raising the stirring power or frequency appropriately can gain a better shape of primary α-Al grains;but if the stirring power or frequency is increased to a certain value(1.72 kW or10 Hz),the shape of primary α-Al grains cannot be obviously improved and spherical primary α-Al grains distributed homogeneously can be still obtained. The semisolid AlSi7Mg alloy slurry with large capacity was prepared by low superheat pouring and week traveling-wave electromagnetic stirring. The effects of electromagnetic stirring power and frequency on the shape and distribution of primary α-Al grains in the AlSi7Mg alloy slurry were discussed. experimental results show that the AlSi7Mg alloy slurry with fine and spherical primary α-Al grains distributed homogeneously can be obtained. Under the condition of low superheat pouring and week traveling-wave electromagnetic stirring, when the pouring temperature is 630 ° C, raising the stirring power or frequency adequately gain better shape of primary α-Al grains; but if the stirring power or frequency is increased to a certain value (1.72 kW or 10 Hz), the shape of primary α-Al grains can not be obviously improved and spherical primary α-Al grains distributed homogeneously can be still obtained.