The Li2Mo4O13 melt structure and its Raman spectral characteristics are the key for establishing the composition-structure relationship of lithium molybdate melts. In this work, Raman spectroscopy, factor group analysis, and density functional theory (DFT) were applied to investigate the structural and spectral details of the HLi2Mo4O13 crystal and a Li2Mo4O13 melt. Factor group, analysis shows'that the crystal has 171 vibrational modes (84A(g) + 87A(u)), including three acoustic modes (3A(u)), six librational modes (2Ag + 4A(u)), 21 translational modes (7A(g) + 14A(u)), and 141 internal modes (75(Ag) + 66A(u)). All of the A(g) modes are Raman-active and were assigned by the DFT method. The Li2Mo4O13 melt structure was deduced from the H-Li2Mo4O13 crystal structure and demonstrated by the DFT method. The results show that the Li2Mo4O13 melt is made up of Li' ions and Mo(4)O(13)(2-)groups, each of which is formed by four corner-sharing MoO3 circle divide/MoO circle divide(2) tetrahedra (0 = bridging oxygen). The melt has three acoustic modes (3A) and 54 optical modes (54A). All of the optical modes are Raman active and were accurately assigned by the DFT method.