Amminelithium borohydride (LiBH4·NH3) is one of the most hydrogen-rich inorganic materials, showing potential application for hydrogen storage. In this paper, the dehydrogenation of LiBH4·NH3 was promoted significantly through heating in ammonia atmosphere which demonstrated that the coordinate between NH3 and LiBH4 is a crucial factor in inducing the hydrogen release for this system. Meanwhile, several metal hydrides LiH, NaH, and CaH2 were found to be effective in promoting the dehydrogenation of LiBH4·NH3. Among the studied additives, the effect of LiH, as an example, was discussed in detail. It was found that the promotion of dehydrogenation through LiH is due to the reaction: 3LiH + 3LiBH4·NH3 → Li4BN3H10 + 2LiBH4 + 3H2, releasing hydrogen from 60 °C.