Abstract: Low-frequency electromagnetic (LFE) field was applied to the conventional hot-top casting process, and thermocouples were used to measure the cooling process from different edge positions to the center of an ingot in the steady-state of casting process, thus getting the cooling curves and temperature distribution within the ingot. The effects of LFE field on the solidification process, macrostructure and thickness of surface segregation layer during the conventional hot-top casting of 6063 aluminum alloy were analyzed. The results showed that the forced convection resulting from Al melt in LFE field makes the temperature distribution more uniform to dissipate the overheat of Al melt so as to enable the temperature in the pool to be lower than the liquidus temperature of 6063 aluminum alloy and to increase the number of nucleating particles inside the pool, thus providing the fine and homogeneous macrostructure without any grain refiner added in and reducing the depth of liquidus cave. Heat transfer between ingot and mold is then intensified by the quickened flow velocity of Al melt. As a result, the initial solidifying point on the ingot surface in mold moves upwards to decrease the height of contact zone between the melt and mold so as to improve the surface quality of ingot.