In this paper, the effect of adding 1.0 wt.% Ce on the as-cast microstructure and mechanical properties of the Mg-3.8Zn-2.2Ca (wt.%) magnesium alloy were investigated. The results indicate that, after adding 1.0 wt.%Ce to the Mg-3.8Zn-2.2Ca alloy, small amounts of Mg12Ce phase are formed and an obvious equiaxed trendance is observed. At the same time, the average grain size decreases from 234mm to 71mm and the morphology of some Ca2Mg6Zn3 phases changes from initial coarse blocks to fine particles. In addition, adding 1.0 wt.%Ce to the Mg-3.8Zn-2.2Ca alloy also improve the tensile and creep properties of the alloy. Further investigations need to be considered in order to optimize the amounts of Ce additions and understand its effects on the tensile and creep properties and age-hardening behaviour.