2LiBH4/MgH2 hydrogen storage composite was prepared by ball-milling technology, and its microstructures and hydrogen storage properties were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and hydrogen storage measurements. The effects of Ce-based catalysts on the hydrogen storage properties of the composite were studied. The results show that hydrogen release of 2LiBH4/MgH2 composite is a two-step process, i.e., the first is the decomposition of MgH2 and the second is the reaction between LiBH4 and Mg just produced. Ce or CeF3 addition can improve the dehydrogenation of 2LiBH4/MgH2 composite. Ce mainly improves the behavior of the second step reaction while CeF3 influences the behavior of the two steps greatly. For the 2LiBH4/MgH2 composite with addition of 5 mol% CeF3, the total hydrogen capacity reaches 10.6 wt% at 450 oC and the initial hydrogen release temperature is decreased by around 100 oC. LiBH1-xFx is formed by partial substitution of F- for H-, which decreases the decomposition temperature of LiBH4.