Mg-5Li-3Al-2Zn-2.1Ce alloy was prepared by vacuum casting combined with extrusion deformation.The microstructure of the alloy was analyzed by OM（optical microscopy）

SEM（scanning electron microscopy）

XRD（X-ray diffraction）and EDS（energy dispersed spectrometer）

and the compressive behaviors were tested at 1.67×10

-4

、1×10

-3

、5×10

-3

and 1×10

-2

s

-1

at room temperature.The results show that Mg-5Li-3Al-2Zn-2.1Ce alloy is composed ofα-Mg

Al

2

Ce and Al

4

Ce phase.The maximum compression strength and the maximum strain of the alloy reach 516.69 MPa and 19%

respectively.At different strain rates

the strain rate sensitivity of the alloy is negative

and there exists a large number of twins in the alloy with high strain rate.The deformation mechanism at low strain rate compression is characterized by the lattice slip coordinated with recrystallization

and the deformation mechanism at high strain rate is characterized by the lattice slip coordinated with twins.