Calcium borohydride, Ca(BH4)2, one of the promising candidates for efficient hydrogen storage, has been synthesized successfully by the metathesis reaction between magnesium chloride and sodium borohydride in tetrahydrofuran in which the insoluble byproduct sodium chloride can be easily removed. And the hydrogen storage properties of its related Ca(BH4)2-4LiNH2 composite system with the presence of cobalt containing species as additives are systematically investigated. A doping of 5 wt. % CoCl2 considerably decreases the dehydrogenation temperature of a mixture of Ca(BH4)2-4LiNH2. More than 4.5 and 7 wt. % of hydrogen can be released at temperatures as low as ca. 165 and 178 °C, respectively. The effective catalytic species is determined to be cobalt particle which is formed on-site during ball milling process, having superior catalytic performance to cobalt powder as a catalyst. In addition, the results show that the amount of by-product NH3 is less when dehydrogenated by volumetric release than by thermogravimetric analysis (TG), i.e., evolved NH3 can react with borohydride for hydrogen release in closed reactor.