Abstract: A bis (8-hydroxyquinoline)-type flexible ligand H₂L was designed and synthesized with three steps using 8-hydroxyquinalidine as a raw material. Reacting the flexible ligand H₂L with Cd(Ⅱ) ions, a cadmiumbased complexCd₂(L)(NO₃)₄ was obtained. ¹H-NMR, mass spectrometry, X ray single crystal diffraction and X ray powder diffraction were used to characterize the structure of ligand and cadmium complex, and LS 50B fluorescence spectrometer was used to characterize the fluorescence properties of ligand and cadmium complex. The results show that the cadmium complex is a binuclear molecular complex. There are abundant supramolecular interactions, such as π-π stacking and C-H…O hydrogen bonding. When the excitation wavelength is 340 nm, the maximum emission wavelengths of the flexible ligand H₂L and cadmium complex are 548, 449 nm respectively.