The effect of electromagnetic field on the solidification structure of HMn084 brass (Cu-20%Zn-7.5%Mn-5.5%Al-1.5%Si-1%Fe-0.5%Pb in mass%) had been investigated in this paper. The results show that the as-cast structure of HMn084 brass is composed of matrix β-phase, small amount of α-phase and silicide (Mn, Fe)5Si3. Applying electromagnetic field during the solidification of HMn084 brass can refine grain and silicide phase, promote the uniform distribution of silicide phase. The morphology of silicide phase changes from coarse acicular and massive shape to fine acicular and massive shape. The above-mentioned effects become more obvious with the increasing in current intensity.