Three lanthanide complexes [LnL₃(H₂O)]PMo₁₂O₄₀·CH₃CN (Ln = Dy³⁺ for 1, Ln = Ho³⁺ for 2, Ln = Lu³⁺ for 3, L = tetraethyl ethylenediphosphonate) have been synthesized, and characterized by single-crystal X-ray diffraction, elemental analysis, IR, PXRD, thermogravimetric analysis and terahertz time-domain spectroscopy (THz-TDS). Structural analysis results show that they have the same coordination mode and similar steric structures. Complexes 1～3 all crystallize in the monoclinic crystal system with space group P2₁/c. The centered Ln(Ⅲ) obtained a seven-coordinated mononuclear structure by linking with three tetraethyl ethylenediphosphonates and one water molecule, resulting in a three-dimensional supramolecular structure through hydrogen bonding. The three complexes have good adsorption properties for rhodamine B (RhB) in powder state. Moreover, terahertz time-domain spectroscopy (THz-TDS) was applied to represent the structures of complexes and ligands, which will provide useful information for establishing bridge between THz and complex structure in coordination chemistry.