Abstract: Polyoxometalate (POM)-supported inorganic-organic hybrid compounds have attracted extensive attention for its superior physical and chemical properties. It is important to research. H₂pcaH₃SiW₁₂O₄₀·2H₂O(1) (pca = Pyridine-4-carboxylic acid), which has been obtained by hydrothermal methods and characterized by single-crystal X-ray diffraction analyses, IR spectra, powder X-ray diffraction, and thermal analyses. It belongs to monoclinic crystal system and C2/m space group. Hydrogen bonds of ligand and SiW₁₂O₄₀^4- lead to a three-dimensional supramolecular structure. In addition, fluorescence spectra was also investigated. The experimental results show that the compound has a fluorescence absorption peak at λ = 410 nm, and also has good thermal stability. This work extends POM-supported inorganic-organic hybrid compounds, and it will be a strong foundation for further application.