The Mg–6Zn– xCe–0.6Zr ( x = 1, 2) alloys were subjected to a dynamic compression experiment, and the change in microstructure was noticed and studied. The primary components of two alloys are α-Mg matrix, Mg7Zn3 phase, and (Mg1− xZn x)11Ce phase. The two alloys have grain diameters of 2.8 and 3.2 μm, respectively. The dynamic compressive mechanical characteristics of the two alloys show a positive strain-strengthening effect, with Mg–6Zn–1Ce–0.6Zr alloy having somewhat higher values than Mg–6Zn–2Ce–0.6Zr alloy. At a strain rate of 500 s−1, {10[Formula: see text]2} tensile twin is the dominant deformation mechanism for two alloys, but the Mg–6Zn–2Ce–0.6Zr alloy is more prone to produce {10[Formula: see text]2} tensile twin. With the increase of the strain rate, the dominant deformation mechanism changes from {10[Formula: see text]2} tensile twin to pyramidal slip.