The intermediate frequency electromagnetic oscillation technique was used to obtain the ideal semi-solid metal slurry and billet of the aluminum alloy ZL104. In this research, the proper number of oscillation was mainly discussed when using the intermediate frequency electromagnetic oscillation technique to produce semi-solid slurry. The influence of the electromagnetic fields generated by electromagnetic stirrer on the microstructure of the semi-solid slurry and billet was also analyzed. The results indicate that the method is easy to operate with short process and low-cost equipment. The semi-solid materials obtained from this method are uniform and do not show a skin-effect caused by the electromagnetic field distribution unevenness. Minimum average equivalent diameter of primary α-Al is 28 μm, and the shape factor of primary α-Al is 0.89.