As one of the highest temperature magnesium alloys, Mg-Zn-Cu ternary alloys are draw much attention in recent years. However, the previous investigations were mainly focused on their microstructure and mechanical properties. The investigations on their solidification and hot tearing behaviors are barely discussed. In order to improve the industrial applications of Mg-Zn-Cu alloy, it is necessary to better understand the solidification pathways, phase constituent and hot tearing susceptibility (HTS) of these alloys. In this work, the effect of Cu additions on the hot tearing behaviors of Mg-7Zn-xCu-0.6Zr (x=0, 1, 2, 3) alloys was studied using with T type hot tearing mold. The microstructure and the morphology of cracking zone of Mg-7Zn-xCu-0.6Zr (x=0, 1, 2, 3) alloys were observed by XRD and SEM, respectively. The hot cracking susceptibility of Mg-7Zn-xCu-0.6Zr (x=0, 1, 2, 3) alloys were characterized by the measurement of crack volume. The experimental results show that the grain sizes of Mg-7Zn-0.6Zr alloys were refined by addition of Cu element. Meanwhile, the amount of eutectic phase was increased with increasing the Cu content and the separated dendritic was refilled by the eutectic phase. Hot tearing susceptibility of Mg-7Zn-0.6Zr was decreased with increasing of Cu content. The Mg-7Zn-0.6Zr and Mg-7Zn-1Cu-0.6Zr alloys were completely broken. The hot cracks of Mg-7Zn-xCu-0.6Zr (x=0, 1, 2, 3) alloys were formed by liquid film, solidification shrinkage and interdendritic bridge.