Nanostructured lithium imide (Li2NH) was synthesized by solid ion exchange reaction of Li3N and LiNH2. The average crystallites diameter is around 12 nm. Hydrogen adsorption study indicated that the enthalpy change for the hydrogenation over this material is ~ 35 KJ/mol, which is lower than the reported ones (-60-65 KJ/mol), also lower than theoretical prediction value (~ 45 KJ/mol). This enthalpy change as well as 6.5 wt% of reversible hydrogen capacity suggests that this lithium imide is a good candidate for on-board hydrogen storage. Further modifying with Mg, Ti, etc over lithium imide did not increase the corresponding hydrogen adsorption activity while the cycle stability was markedly enhanced.