The electrochemical reactivity of Li3N with transition metals (M=Mn, Fe, Co, Ni) is examined by discharge/charge, cyclic voltammetry, X-ray diffraction and X-ray photoelectron spectroscopy measurements. An attempt is made to understand this reversible electrochemical reaction of transition metals with Li3N from the chemical reactions point of view. Density functional theoretical calculation results suggest that a stable complex MNLi3 could be formed by the insertion of transition metal in Li3N with exothermic as an intermediate, subsequent the decomposition process of these insertion compounds should make a main contribution to release Li.