Abstract: The structure of V₂O₅-P₂O₅-Sb₂O₃-Bi₂O₃ glass and its state of crystallization were studied by means of infrared spectroscopy and X-ray diffraction analysis. The results indicate that, in this glass, V and P exist mainly in the form of a single-stranded linear (VO₃)_n and an isolated (PO₄) tetrahedral with no double bond. Partial V and P are connected through O, forming an amorphous structure of layered vanadium phosphate. Trivalent Sb³⁺ and Bi³⁺ open the V=O bond and appear in interlayers, so a weak three-dimensional structure is connected successfully. Along with the substitution of Sb₂O₃ for partial V₂O₅ or that of P₂O₅ for partial V₂O₅, the network structure of the glass is reinforced, and the crystallization is reduced.