The Li–Mg–N–H system is a very promising hydrogen storage material due to its high capacity, reversibility and moderate operating conditions. In this work, the mixture of LiMgN and LiH produced by ball milling with a mixture of Li 3 N–MgH 2 at a 1:1M ratio starts to absorb hydrogen at 130°C under 10MPa. Effects of the additives (5mol% Ti, 5mol% TiCl 3 and 5mol% LiNH 2 ) on the microstructural evolution and hydrogen storage properties were studied. Among the additives, Ti and TiCl 3 are both detrimental for hydrogen storage properties including hydrogen absorption/desorption capacity and hydrogenation kinetics, but, LiNH 2 is the most effective additive for improving the hydrogen storage properties. With an addition of 5mol% LiNH 2 , the hydrogen absorption capacity is improved from 3.2wt% to 3.7wt% and the onset absorption temperature is decreased from 130°C to 90°C. The improvement of hydrogen properties is due to well-distributed nano-particles of the hydrogenated/dehydrogenated products.