In the producing process of 7075 aluminum alloy by CREM method, the effects of electromagnetic field with low frequency on the evolution of solidifying front shape, non-dendritic structure, liquidus and solidus temperature of non-equilibrium freezing, solidification interval, flow pattern and temperature field have been experimentally investigated. An explanation is also given to the mechanism of CREM process on restraining macro-segregation of solute elements in 7075 aluminum alloy ingot by DC cast.