Three kinds of different phases of Mg-xLi-1Al alloys with x=5 (full α LA51), 9 (dual-phase LA91), and 14 (rich-βLA141) were prepared by vacuum melting method. Their microstructure and damping capacities were investigated by optical microscopy, X-ray diffractometry, and dynamic mechanical analysis. The results show that the addition of Li changes the crystal structure of the alloys and causes new damping mechanisms to emerge. And the appearance of BCC structure makes the damping performance improved remarkably. The lower the elastic modulus is, the smaller the strain is and even the slower the acceleration is. The dual-phase alloy shows a better damping capacity while the temperature changes. Furthermore, all three alloys have two significant peaks:P1 caused by the movement of dislocations on the basal planes and P2 caused by the sliding of grain boundaries.%采用真空熔炼法制备三种不同相态的Mg-xLi-1Al三元合金，并使用光学显微镜、X射线衍射分析及动态力学分析仪研究其显微组织及阻尼性能。结果表明：由于锂含量的增加，合金的相结构发生转变且出现新的阻尼机制，其中 BCC 结构的出现使阻尼性能显著提高，同时弹性模量的减小也使临界应变振幅值降低。两相共存状态的合金随温度变化表现出较高的阻尼现象，并在低温与高温区均出现两个较为明显的峰值，其中低温区的P1峰是位错阻尼峰，高温区的P2峰是晶界阻尼峰。
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