ZK60 magnesium alloy ingots with the diameter of 500 mm were fabricated by the semi-continuous casting.The melt was well purified by low pressure transferring the melt and standing technique.The effects of the casting parameters on the metallurgy quality of the ingots were investigated and the reasonable parameter windows were established.The metallurgy defects were analyzed to understand the formation mechanism of the defect.The characteristics of the microstructure was also observed.The results reveal that the casting velocity has the significant effect on the metallurgy quality of the ingot.The through-crack can be formed in the center zone of the ingot in case of using the higher velocity or the higher water flow.The microstructure of the large-scale ZK60 magnesium alloy is composed of equiaxed grain withα-Mg matrix and the second phases MgZn2 which are precipitated in the grain and the grain boundary discontinuously.The grain in the edge of the ingots is much more refined than that of the center of the ingots.