A356/Zn bimetal composite plate was prepared by double liquid composite casting.The interfacial microstructure and interface cross sectional height of the composite plate were adjusted by changing the pouring sequence of the two alloys and the pouring temperature of A356 aluminum alloy.The microstructure and mechanism of composite layer formation at the A356/Zn interface were evaluated by scanning electron microscope（SEM）and energy dispersive spectrometer（EDS）.The results reveal that the interface of A356/Zn bimetal composite plate presents desirable metallurgical bonding with A356 melt at660 ℃

where a well-developed dendrite can be formed with interface cross sectional height of about 2 mm.The interface can be divided into three regions based on the generation phase.When the pouring temperature of A356 aluminum alloy is 620℃

the dendrites in the composite interface are reduced obviously or even absent with the width of composite interface decreased to about 1 mm.