Abstract: Investigates experimentally and comparatively the as-cast microstructure and Cu macrosegregation of 2024 Al alloy ingots by HDC (horizontal direct chill) continuous casting process in low-frequency electromagnetic field and those by conventional horizontal continuous casting process, where the cross-sectional area of specimens is 40 mm × 200 mm. The two different specimens were both inspected by optical microscopy and chemically analyzed sampling from their cross-sectional areas. The result showed that the low-frequency electromagnetic field can greatly improve the microstructure with grain refining, and reduce the Cu macrosegregation on cross-sectional area for uniform distribution.