The solidification structures of AZ61 magnesium alloy under different electromagnetic fields were observed.It is found that the solidification structure of AZ61 magnesium alloy consists of basically equi-axed grain under static magnetic field or combination of static field with alternating current（AC）

while dendrite in the rapid solidification structure can be increased with a certain orientation under the combination of static magnetic field with direct current（DC）.The grain boundary in the solidification structure is composed of magnesium matrix and continuous net-like compound in static field

while it is composed of magnesium matrix and net-like as well as spot-like Mg-Al-Zn compound in combination of static magnetic field with alternating current.The absence of continuous net-like compound at grain boundary can be observed

and the discontinuous lamellar structure is dis-tributed in the magnesium matrix in combination of static magnetic field with direct current.