Mg-8.5Li-3Al-xCe (x=0, 1, 3) alloys were prepared with vacuum induction melting method. Then the aging behavior of the Mg-8.5Li-3Al-xCe alloy was investigated. The results show that Ce has an obvious effect on the aging-hardening process. With the increase of Ce content, the aging hardness increases and the over-aging softening is suppressed to some extent. The aging hardness increase and the over-aging softening decrease of Mg-8.5Li-3Al-xCe (x=0, 1, 3) alloys is mainly attributed to that Ce inhibits the generation of age-hardening phase MgLi2A1 and over-aging softening phase AlLi. Ce can hinder the over-aging process in Mg-Li-Al alloys