Based on the non-uniform distribution of magnetic field within the ingot caused by its interactions during the dual-ingot low-frequency electromagnetic semi-continuous casting process, a three-dimensional finite element model was constructed. This model was meshed and calculated with the ANSYS software, and the distribution of magnetic field in low-frequency semi-continuous casting mould was obtained. The influence of the distance and current directions between two coils on magnetic field distribution in the ingot was studied. Calculated results showed that, during dual-ingot low-frequency electromagnetic semi-continuous casting process, whether the current was in the same direction or the reverse, magnetic field density on the remote end should be greater than that on the proximal of the same ingot; when the current directions of nearby coils were reverse, the magnetic intensity on ingot was higher than that with the same directions; as the distance between coils increased, the distal and proximal difference of magnetic flux density declined. Based on the results, a casting mould for dual-ingot electromagnetic semi-continuous casting ø152mm 7075 aluminum alloy was designed and produced. The experimental results showed that when the current directions of nearby coils were reverse, the as-cast macrostructures were a little bit better than that with the same directions. Moreover, when the current directions were reverse, the heterogeneity of the as-cast inner structure could be almost ignored.